The ratio of Albert's age to Jack's age is 2 : 1. Last year, their average age was 20. How old will Jack be in 3 years' time?
| |
Albert |
Jack |
Total |
| Before |
2 u - 1 |
1 u - 1 |
40 |
| Change |
+ 1 |
+ 1 |
|
| After |
2 u |
1 u |
42 |
Total age of Albert and Jack this year
= 2 u + 1 u
= 3 u
Total age of Albert and Jack this year
= 2 x 20 + 1 + 1
= 40 + 2
= 42
3 u = 42
1 u = 42 ÷ 3 = 14
Jack's age in 3 years' time
= 1 u + 3
= 1 x 14 + 3
= 14 + 3
= 17
Answer(s): 17
