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A3.10 · Make and justify purchasing decisions using multiple criteria

Learn to make and justify purchasing decisions using multiple criteria through clear examples and targeted practice.

Ontario Grade 11 Mathematics

Earning and Purchasing

MEL3E study topic A3.10 — compare options and explain your choice

Imagine that your workplace needs a new label printer. One model costs less, another prints faster, and a third has a longer warranty. Which one is the best choice? There may not be one answer that works for everyone. A sound purchasing decision depends on the buyer’s needs. In this lesson, you will choose criteria, compare options, and explain why your choice fits the situation. A criterion is one feature used to judge an option. Criteria can include price, quality, size, durability, warranty, or how well an item meets a task. The important point is to compare the options fairly and use evidence to support your decision.

What you will learn

Identify criteria that matter for a purchase.
Compare options using the same criteria and reliable information.
Use a calculator or spreadsheet to check costs and organize comparisons.
Make a purchasing decision and justify it with evidence from more than one criterion.

1. Start with the need and the criteria

Before comparing products, be clear about what the purchase must do. A worker buying safety boots may need a required safety rating and a comfortable fit. A family choosing a refrigerator may care about price, size, and energy use. The situation determines which criteria matter.

A criterion is a feature you use to compare choices. Some criteria are essential. For example, if boots must meet a workplace safety rule, a pair that does not meet it is not a suitable choice, even if it costs less. Other criteria help you decide between suitable options. These might include comfort, expected life, or warranty.

A fair comparison uses the same criteria for each option. It also uses information that can be checked, such as a price tag, product label, store policy, or written quote. If an important fact is missing, ask for it or mark it as unknown. Do not treat a guess as a confirmed feature.

First identify the task or need.
Separate must-haves from preferences.
Use the same criteria for every option.

2. Compare evidence, not just the price tag

The lowest sticker price is not always the best purchase. An item that is too small, wears out quickly, or does not suit the task may lead to more expense or frustration. Compare the features that matter for the real situation.

A useful comparison can include numerical evidence, such as price or warranty length, and descriptive evidence, such as whether an item fits a particular task. Keep the units clear. Compare warranty periods in months or years, and compare prices in the same currency. Check whether a listed price includes delivery, required accessories, or taxes if those details affect the decision.

A calculator helps with simple totals. A spreadsheet can place options in rows and criteria in columns, making it easier to spot differences. For example, enter each price and add any required delivery fee. Check that the numbers match the source documents. A spreadsheet organizes evidence; it does not decide what matters most to you.

If you use a rating such as 'good' or 'fair', explain what it means. One person’s 'good quality' may mean something different to another person. Whenever possible, connect the rating to a clear fact, such as the product’s stated material or a feature needed for the job.

Check what is included in a quoted price.
Use a calculator or spreadsheet to organize and verify figures.
Explain ratings and do not assume missing information.

3. Make and justify the decision

After comparing the options, decide which criteria matter most in this situation. A buyer may value a lower price, but not if the item fails an essential need. Another buyer may accept a higher price for a feature that will be used often. The reasons should match the needs you identified at the start.

A justification is an explanation supported by evidence. State your choice, name the criteria that influenced it, and refer to specific information from the comparison. You can also mention a trade-off: one option may cost less, while another has a longer warranty. A trade-off is something you gain while giving up something else.

There may be more than one reasonable choice when people have different needs. A strong answer does not need to claim that one product is best for everyone. It needs to show that the choice fits the stated situation and is based on a fair comparison.

Choose based on the needs and criteria, not on price alone.
Support your choice with facts from the comparison.
Mention a relevant trade-off or limitation.

4. A practical decision routine

Use a short routine when you are comparing a purchase. First, describe what the item needs to do. Next, list a few useful criteria and identify any must-haves. Gather the same type of information for each option. Use a calculator or spreadsheet for totals, then check the entries against the labels or quotes.

Finally, choose the option that best fits the situation and explain why. If the evidence does not show an important difference, say so. You may need more information before deciding. This is especially sensible when a feature affects safety, suitability, or the full cost.

The routine keeps the decision focused. It also makes your reasoning easy for someone else to follow, such as a supervisor approving a purchase or a family member comparing products.

Name the need, criteria, and must-haves.
Collect comparable information and check calculations.
Choose, justify, and ask for missing information when needed.

Printer comparison from the workroom example

Model	Price	Labels per minute	Warranty
A	CAD 145	18	12 months
B	CAD 175	30	18 months
C	CAD 130	12	6 months

Worked example

Choosing a printer for a small workroom

A workroom prints short job labels each day. The required label size is available for all three models. Model A costs CAD 145, prints 18 labels per minute, and has a 12-month warranty. Model B costs CAD 175, prints 30 labels per minute, and has an 18-month warranty. Model C costs CAD 130, prints 12 labels per minute, and has a 6-month warranty. The supervisor says quick printing matters, but the printer must also be affordable. Which model is the best fit?

Identify the need
All models can make the required label size, so each meets the stated must-have. The supervisor also values speed and affordability. Compare those criteria, and use warranty as another useful point of evidence.
Organize the facts
Place the three models side by side. The figures show that Model B is fastest, Model C costs least, and Model B has the longest warranty. Model A falls between them on all three listed measures.
Connect the evidence to the need
Model B prints 12 more labels per minute than Model A and 18 more than Model C. It costs CAD 30 more than Model A and CAD 45 more than Model C. Its warranty is also longer. The extra speed may help a workroom that prints labels often, but the higher price matters if the budget is tight.
$30=175-145,\quad 45=175-130$
Make and explain a choice
Choose Model B if the workroom can afford CAD 175 and uses the printer often. It best supports the stated need for quick printing, and it has the longest warranty. If the budget cannot stretch to that price, Model A is a reasonable lower-cost compromise: it costs CAD 30 less than B, prints faster than C, and has a longer warranty than C.

Answer: Model B is the best fit when the workroom can afford its price, because it is the fastest and has the longest warranty. Model A is a reasonable alternative if keeping the purchase price lower is more important.

Check: The comparisons are consistent: B costs more than A and C, prints the most labels per minute, and has the longest warranty. The recommendation names the condition that could change the choice.

Worked example

Choosing a delivery option for a supply order

A small business needs 10 storage bins for an upcoming job. Three suppliers offer bins that meet the required size and strength. Supplier North charges CAD 16 per bin and CAD 20 for delivery. Supplier Central charges CAD 18 per bin with free delivery and offers a 30-day return period. Supplier South charges CAD 15 per bin and CAD 35 for delivery, with no return information listed. The business wants to keep the total cost low but may need to return bins that do not fit the work area. Which supplier should it choose?

Choose relevant criteria
All three suppliers meet the stated size and strength needs. Compare the full order cost and the return information, because the business may need to send bins back. The same number of bins is being ordered from each supplier, so the price comparison is fair.
Calculate each order cost
Multiply the price per bin by 10, then add delivery where it applies. This gives the listed cost before any tax, since tax information was not provided.
$\begin{aligned} \text{North: }10(16)+20&=180\\ \text{Central: }10(18)+0&=180\\ \text{South: }10(15)+35&=185 \end{aligned}$
Compare the other evidence
North and Central each cost CAD 180 before tax, while South costs CAD 185. Central states a 30-day return period. North and South provide no return information in the offer, so do not assume that returns are allowed or refused.
Make and justify the choice
Choose Central if the return period is important. It ties with North for the lowest listed order cost and provides clear return information. If the business is not concerned about returns, North has the same listed cost, but it should ask about the return policy before ordering. South is not the lowest-cost option on the information given.

Answer: Supplier Central is the strongest fit because it costs CAD 180 before tax, matching North’s total, and it clearly offers a 30-day return period.

Check: North totals CAD 180, Central totals CAD 180, and South totals CAD 185. The recommendation uses both total cost and return information.

Common mistakes and how to avoid them

Choosing the option with the lowest sticker price without checking other needs.

Correction: Compare the criteria that matter for the task, including any must-have features and costs such as delivery.

Assuming an unstated feature is included.

Correction: Mark the information as unknown and ask the seller before deciding when it could affect the purchase.

Giving a choice without explaining the evidence.

Correction: Name the criteria and use specific facts, such as prices, speeds, warranty periods, or return terms.

Lesson summary

A criterion is a feature used to compare purchase options.
Identify the need and must-haves before comparing products.
Use comparable information and check calculations with a calculator or spreadsheet.
A strong purchasing decision fits the situation and is justified with evidence from more than one criterion.

Check your understanding

Question 1

A café needs a small blender for occasional use. Three suitable models meet its size needs. Model P costs CAD 80 and has a 12-month warranty. Model Q costs CAD 95 and has a 24-month warranty. Model R costs CAD 70 and has a 6-month warranty. The café has a firm CAD 85 limit and wants a longer warranty if possible. Which choice best fits these stated needs?

Model Q, because it has the longest warranty, even though it is over the limit.
Model P, because it is within the limit and has a longer warranty than Model R.
Model R, because it has the lowest price, so its warranty does not matter.
correctIndexод

Show answer and explanation

Model P, because it is within the limit and has a longer warranty than Model R.

Model Q exceeds the firm limit. Models P and R are within it, and P has a 12-month warranty compared with R’s 6-month warranty. P best matches both stated criteria.

Question 2

A worker is comparing two suitable tool cases. Case L costs CAD 42 and has a 1-year warranty. Case M costs CAD 48 and has a 2-year warranty. If the worker values both price and warranty, which statement is a supported comparison?

Case L is lower in price, while Case M has the longer warranty.
Case M is lower in price and has the longer warranty.
Case L has the longer warranty because it costs less.
correctIndex

Show answer and explanation

Case L is lower in price, while Case M has the longer warranty.

CAD 42 is less than CAD 48, and 2 years is longer than 1 year. The first statement accurately reports both criteria without claiming one case is best for every buyer.

Key terms

Criterion: A feature used to compare or judge options.
Must-have: A requirement an option needs to meet to suit the purchase.
Trade-off: A gain in one area that comes with giving up something in another area.
Justification: A reason for a decision that is supported by relevant evidence.

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About this lesson

Published by DoAssignment. This AI-assisted lesson follows Ontario Grade 11 Mathematics (MEL3E), expectation A3.10. It is a study resource, not an official curriculum publication.

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