A stationery company packed 1500 notebooks in one batch. 28% of the notebooks had plain covers. The rest had printed covers.
- How many notebooks had plain covers?
- How many notebooks did NOT have plain covers?
- Of the notebooks that did NOT have plain covers, 40% were ruled. How many notebooks were ruled?
Need a hint?
For (c), work out the notebooks that did NOT have plain covers first, then take 40% of that number, not of 1500.
Worked answer
- (a) 28% of 1500 = 1500 × 28 ÷ 100 = 420 notebooks with plain covers.
- (b) 1500 − 420 = 1080 notebooks did not have plain covers.
- (c) 40% of 1080 = 1080 × 40 ÷ 100 = 432 notebooks were ruled.
Answer: 432 notebooks
The mistake this question tests
Habit
Fraction of a remainder
Taking 40% of the whole batch of 1500 (giving 600) instead of 40% of the 1080 printed-cover notebooks.
How to fix it at home →More PSLE percentage questions
Structured · 4m
Priya's money was used only for bus fares, lunch, clothes and savings
See the answer →MCQ · 2mPriya spent 40% of her pocket money on books and 1/4 of the remaining money on stationery
See the answer →Structured · 3mHui Min had a roll of ribbon
See the answer →MCQ · 2mNurul ran a second-hand book stall at a community fair
See the answer →MCQ · 2mA fruit stall had 250 fruits
See the answer →Short answer · 2mA bicycle shop had 960 bicycles in stock
See the answer →Practise PSLE percentage until the mistakes stop.
Three PSLE questions, free, no sign-up. You’ll see exactly where the marks went. Then 7 days of everything for S$4.99.