Question

The average age of three boys is 25 years and their ages are in the ratio 3:5:7. The age of the youngest boy is (a) 6/7 (b) 7/8 (c) 9/8 (d) 1/3

Answer 1

Answer:

None of the give options. The correct answer is 15 years.

Step-by-step explanation:

Let the age of the boys be '3x', '5x' and '7x'

Average age of boys = 25 years

Then, according to the given question;

Since,

Average=Sum of observation/No. of observation

(3x + 5x + 7x) / 3 = 25 years

=> 15x / 3 = 25 years

=> x = (25x3) /15 years

=> x = 75/15 years

Dividing by common factor 15, we get;

x = 5 years

Thus, age of youngest boy be '3x'will be 3(5) year =15 years.

So, the options you have given are incorrect and the real answer is 15 years.