Bobby is
r years old. Ethan is six times as old as Bobby and Ken is 10 years younger than Ethan.
- Express Ken's age in terms of r.
- Bobby is 10 years old as of now. ln how many years' time will Ken be 3 times as old as Bobby?
(a)
Bobby's age =
r years
Ethan's age = 6
r years
Ken's age = (6
r - 10) years
(b)
r = 10
Difference in age remains unchanged.
Difference in age between Ken and Bobby
= (6
r - 10) -
r = 6
r -
r - 10
= 5
r - 10
= 5 x 10 - 10
= 40 years
Difference in the age when Ken will be 3 times as old as Bobby
= 3 u - 1 u
= 2 u
2 u = 40
1 u = 40 ÷ 2 = 20
Number of years' time so Ken will be 3 times as old as Bobby
= 20 - 10
= 10 years
Answer(s): (a) (6
r - 10) years; (b) 10 years
