On Monday, a kite workshop used 45 sheets of green paper and 75 sheets of blue paper to make kites.
- Write the ratio of the number of green sheets to the number of blue sheets in its simplest form. [1]
- On Tuesday, the workshop used 27 green sheets, and the same ratio of green to blue sheets was kept. How many blue sheets were used? [1]
- On Wednesday, the workshop used 160 sheets of paper altogether, and the ratio of green to blue sheets was again the same. How many green sheets were used? [2]
Need a hint?
For (a), find a number that divides both 45 and 75. For (c), first find the total number of parts before dividing 160.
Worked answer
- (a) 45 : 75; divide both by 15 to get 3 : 5.
- (b) 27 green ÷ 3 = 9, so 1 part is 9 sheets; blue = 9 × 5 = 45 sheets.
- (c) Total parts = 3 + 5 = 8; 160 ÷ 8 = 20 sheets per part.
- (c) Green sheets = 3 × 20 = 60 sheets.
The mistake this question tests
Simplest form in final fraction answers
Pupils often divide only one number, or use the total ratio parts without adding them first, which gives a wrong number of sheets in part (c).
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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