The ratio of Ryan's age to David's age is 10 : 7. Next year, their average age will be 18. How old will Ryan be in 2 years' time?
| |
Ryan |
David |
Total |
| Before |
10 u |
7 u |
34 |
| Change |
+ 1 |
+ 1 |
|
| After |
10 u + 1 |
7 u + 1 |
36 |
Total age of Ryan and David this year
= 10 u + 7 u
= 17 u
Total age of Ryan and David this year
= 2 x 18 - 1 - 1
= 36 - 2
= 34
17 u = 34
1 u = 34 ÷ 17 = 2
Ryan's age in 2 years' time
= 10 u + 2
= 10 x 2 + 2
= 20 + 2
= 22
Answer(s): 22
