The ratio of Eric's age to Jack's age is 5 : 2. Last year, their average age was 13. How old will Jack be in 2 years' time?
| |
Eric |
Jack |
Total |
| Before |
5 u - 1 |
2 u - 1 |
26 |
| Change |
+ 1 |
+ 1 |
|
| After |
5 u |
2 u |
28 |
Total age of Eric and Jack this year
= 5 u + 2 u
= 7 u
Total age of Eric and Jack this year
= 2 x 13 + 1 + 1
= 26 + 2
= 28
7 u = 28
1 u = 28 ÷ 7 = 4
Jack's age in 2 years' time
= 2 u + 2
= 2 x 4 + 2
= 8 + 2
= 10
Answer(s): 10
