Siew Ling, Tomas and Umar share $3 600 from a school recycling drive in the ratio 4 : 7 : 9.
- How much money does Siew Ling receive?
- How much more money does Umar receive than Tomas?
Need a hint?
Find the value of one unit first by dividing the total by the total number of units. Then work out each person's share before comparing.
Worked answer
- (a) Total units: 4 + 7 + 9 = 20 units.
- One unit: $3 600 ÷ 20 = $180.
- Siew Ling: 4 units × $180 = $720.
- (b) Umar: 9 units × $180 = $1 620.
- Tomas: 7 units × $180 = $1 260.
- Difference: $1 620 − $1 260 = $360.
The mistake this question tests
Stopped at one part in ratio
Pupils often compare the ratio numbers directly (9 − 7 = 2) and multiply by the total instead of by the value of one unit, or they divide $3 600 by 3 people rather than by 20 units.
How to fix it at home →More PSLE ratio questions
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See the answer →Practise PSLE ratio until the mistakes stop.
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