Hassan had some marbles. He lost 2/5 of them. He then gave 1/2 of the remaining marbles to his brother. At the end, he had 15 marbles left. How many marbles did Hassan lose in the first step?
Need a hint?
Work out what fraction of all the marbles is left at the end first, then find the total.
Worked answer
- After losing 2/5, 3/5 of the marbles remained.
- He gave away 1/2 of 3/5, which is 3/10 of the total, so 3/10 of the total is left.
- 3/10 of the total is 15 marbles, so 1/10 is 5 marbles and the total is 50 marbles.
- Lost in the first step: 2/5 of 50 = 20 marbles.
Answer: 20 marbles
The mistake this question tests
Habit
Fraction of a remainder
Writing 15 as the answer confuses the marbles left at the end with the marbles lost in the first step.
How to fix it at home →More PSLE fractions questions
Short answer · 3m
Mrs Tan baked some cookies
See the answer →Structured · 4mMrs Lim had some eggs
See the answer →MCQ · 2mA florist had an equal number of roses and lilies for sale
See the answer →Short answer · 2mA bakery had some trays of buns
See the answer →Structured · 3mRavi prepared red and blue felt badges for a school charity booth
See the answer →MCQ · 2mOn Monday, Rina drank 3/8 of a bottle of apple juice
See the answer →Practise PSLE fractions 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.