A justified decision names the choice, backs it with a fact from the question, explains why the fact matters, and states when the choice would change. This lesson shows that pattern on one household purchase.
It belongs to the SPM subjects and learning resources section. Teaching online covers the thinking and writing skills; any practical or school-assessed work stays with your school.
What does a justified answer contain?
Use four parts: claim, evidence, reasoning, condition. The first three earn most of the marks. The fourth shows you understand that a decision depends on the household.
- Claim: the choice you recommend.
- Evidence: a figure or fact taken from the question.
- Reasoning: why that fact favours your choice.
- Condition: when the choice would stop being sensible.
Worked example: two bags of rice
This is a worked example. A household of four buys rice.
A 5 kg bag costs RM26 and a 10 kg bag costs RM48. The family uses about 1.2 kg each week and has a cool, dry cupboard with a sealed container.
Step 1: make the options comparable. Find the price for each kilogram.
- 5 kg bag: RM26 ÷ 5 = RM5.20 per kg
- 10 kg bag: RM48 ÷ 10 = RM4.80 per kg
The 10 kg bag saves RM0.40 on each kilogram. Across the whole bag that is RM4.00, because 10 × RM0.40 = RM4.00.
Step 2: test it against the household. At 1.2 kg each week, 10 kg lasts 10 ÷ 1.2 = 8.3 weeks, so a little over eight weeks. The cupboard and sealed container make that storage time reasonable.
Step 3: write the answer.
The household should buy the 10 kg bag.
It costs RM4.80 per kg against RM5.20 for the smaller bag, a saving of RM4.00 a bag. The family will finish it in about eight weeks and can store it in a sealed container in a cool, dry place, so little is wasted. If the family had no dry storage, the smaller bag would be safer.
The mistake that costs marks
The common slip is an opinion answer: “The big bag is better because it is cheaper and more worth it.” It has a claim but no figure, and “worth it” is never explained.
| Part | Opinion answer | Justified answer |
|---|---|---|
| Claim | Buy the big bag | Buy the 10 kg bag |
| Evidence | “It is cheaper” | RM4.80 per kg against RM5.20 per kg |
| Reasoning | “More worth it” | The family finishes it in about eight weeks, so nothing is wasted |
| Condition | None | Only if storage is cool, dry and sealed |
Check yourself
Cooking oil comes in a 2 litre bottle at RM15.00 and a 500 ml bottle at RM4.50. A household uses 250 ml each week and keeps oil in a cool cupboard. Justify which bottle to buy.
Answer
Convert to one unit. 2 litres is 2 000 ml, so the large bottle costs RM15.00 ÷ 20 = RM0.75 per 100 ml. The small bottle costs RM4.50 ÷ 5 = RM0.90 per 100 ml.
The large bottle saves RM0.15 per 100 ml. At 250 ml a week it lasts 2 000 ÷ 250 = 8 weeks.
Answer: buy the 2 litre bottle, because it is RM0.15 cheaper per 100 ml and is used up in eight weeks. The condition is that the oil stays in a cool cupboard, away from heat and light.
What to study next
Next, practise reading quantities in a planning task in interpret quantities in a fictional planning task. Then mix all the skills in the Home Science original practice set.
To check your own justifications against the four parts, use the structured answer self-review. If you want a teacher to read your answers with you, see online one-to-one Home Science tuition.