-
The average age of three boys is 15 yr. If the ratio of their ages is 3 : 5 : 7, What is the age of the oldest boy ?
-
- 7 yr
- 14 yr
- 20 yr
- 21 yr
- None of the above
Correct Option: D
Total age of all three boys
= 3 x 15 = 45 yr
Ratio of ages = 3 : 5 : 7
∴ Age of the oldest boy
= [7/(3 + 5 + 7)] x 45 = (7/15) x 45 = 21 yr
