P5 - Difference Concept

1. Mrs Ong is 45 years old. Her niece is 30 years younger than she is. In how may years' time will Mrs Ong be twice as old as her niece?

2. There were 1240 pupils in School A and 20% more pupils in School B. When an equal number of pupils left each school, the ratio of the number of pupils in School B to that of School A became 5:4. How many pupils were there in School B in the end?

3. Ben's age is 1/3 that of Tom's. In 9 years' time, his age will be 2/3 that of Tom's. How old is Ben now?

4. The ratio of John's age to Ryan's age is 3:1 now. 25 years later, the ratio will become 4:3. How old is John now?

5. Mr Lim had 50% as much money as Mr Ibrahim. After they each spent $200 on a DVD player, Mr Lim had 1/3 as much money as Mr Ibrahim. Find the sum of money Mr Lim had at first.

6. There were 40% as many adults as children on a bus. After 8 children and 8 adults boarded the bus, there were twice as many children as adults. How many adults were on the bus at first?