P2-3 Age Problems

Mr Lim is five times as old as Phillip. He is 52 years older than Phillip.
How old will Phillip be in 8 years' time?

• 22

• 21

• 20

• 18

Tags

CCSS.8.EE.C.8C

Ann is 12 years old when her grandmother is 82 years old. How many years later would her grandmother be six times as old as Ann?

• 2

• 3

• 4

• 5

Answer explanation

The age difference between the 2 same people will always be the same. Hence, difference is unchanged.

Age difference between grandmother and Ann
= 82 years − 12 years
= 70 years

5 units= 70 years

=> 1unit= 70 years ÷ 5= 14 years

Number of years later
= 14 years − 12 years
= 2 years

Ans: 2 years later

Tags

CCSS.8.EE.C.7B

Aunty Ann is 58 years old and her niece, Wei Xin, is 18 years old. How many years later will Aunty Ann be thrice as old as Wei Xin?

• 3

• 4

• 2

• 5

Answer explanation

The age difference between the 2 same people will always be the same. Hence, difference is unchanged.

Age difference between Aunty Ann and Wei Xin
= 58 years − 18 years
= 40 years

2 units= 40 years

=> 1 unit= 40 years ÷ 2= 20 years

Number of years later
= 20 years − 18 years
= 2 years

Ans: 2 years later

Tags

CCSS.7.EE.B.4A

Mrs Ong is be 32 years older than Lynn. This year, Mrs Ong is thrice as old as Lynn. How old will Mrs Ong be 12 years from now?

• 16 years old

• 48 years old

• 60 years old

• 88 years old

Answer explanation

The age difference between the 2 same people will always be the same. Hence, difference is unchanged.

Age difference between Mrs Ong and Lynn = 32 years

2 units= 32 years

1 unit= 32 years ÷ 2= 16 years

3 units= 3 × 16 years= 48 years

Mrs Ong's present age = 48 years old

Mrs Ong's age 12 years from now
= 48 years + 12 years
= 60 years old

Tags

CCSS.8.EE.C.8C

At present, Aunty Pauline is 36 years older than her niece, Betty. Aunty Pauline is 68 years old now. How many years later will she be twice the age of Betty?

• 7

• 6

• 5

• 4

Answer explanation

The age difference between the 2 same people will always be the same. Hence, difference is unchanged.

Age difference between Aunty Pauline and Betty = 36 years

1 unit= 36 years

2 units= 2 × 36 years= 72 years

Number of years later
= 72 years − 68 years
= 4 years

Tags

CCSS.7.EE.B.4A

Emily is 25 years old and her sister, Sarah, is 11 years old. How many years later will Emily be twice as old as Sarah?

• 3

• 7

• 10

• 12

Tags

CCSS.7.EE.B.4A

Uncle John is 60 years old and his nephew, Tim, is 12 years old. In how many years will Uncle John be four times as old as Tim?

• 4

• 5

• 8

• 12

Tags

CCSS.7.EE.B.4A

Uncle Sam was 37 years old when his niece, Belinda, was 16 years old. How many years ago was Uncle Sam four times as old as Belinda?

• 10

• 9

• 8

• 7

Answer explanation

The age difference between the 2 same people will always be the same. Hence, difference is unchanged.

Age difference between Uncle Sam and Belinda
= 37 years − 16 years
= 21 years

3 units= 21 years

1 unit= 21 years ÷ 3= 7 years

Number of years ago
= 16 years − 7 years
= 9 years

Tags

CCSS.8.EE.C.8C

Aunty Fiona was 43 years old when her nephew, Jonathan, was 21 years old. How many years ago was Aunty Fiona thrice as old as Jonathan?

Answer explanation

The age difference between the 2 same people will always be the same. Hence, difference is unchanged.

Age difference between Aunty Fiona and Jonathan
= 43 years − 21 years
= 22 years

2 units= 22 years

1 unit= 22 years ÷ 2= 11 years

Number of years ago
= 21 years − 11 years
= 10 years

Tags

CCSS.8.EE.C.7B

Uncle Kenneth is 40 years older than Jolin. Presently, he is five times as old as Jolin. How many years ago was Uncle Kenneth 47 years old?

• 47

• 50

• 3

• 45

Answer explanation

The age difference between the 2 same people will always be the same. Hence, difference is unchanged.

Age difference between Uncle Kenneth and Jolin = 40 years

4 units= 40 years

1 unit= 40 years ÷ 4= 10 years

5 units= 5 × 10 years= 50 years

Uncle Kenneth's present age = 50 years old

Number of years ago
= 50 years − 47 years
= 3 years

Tags

CCSS.8.EE.C.7B