Banking Quantitative Aptitude Sample Paper Quantitative Aptitude Sample Paper-15

The average age of boys in the class is twice the number of girls in the class. The ratio of boys and girls in the class of 50 is 4: 1. What is the total of the ages (in years) of the boys in the class?                                       [NICL (AO) 2014]

A) 2000

B) 2500

C) 800

D) 400

E) 500

Correct Answer: C

Solution :

Let total age of boys in the class be x yr.

Now, number of boys in the class

\[=\frac{4}{(4+1)}\times 50=\frac{4}{5}\times 50=40\]

\[\therefore \] Number of girls \[=50-40=10\]

Now, according to the question,

\[\frac{{{x}_{1}}+{{x}_{2}}+...+{{x}_{40}}}{40}=2\times 10\]

\[\Rightarrow \] \[{{x}_{1}}+{{x}_{2}}+...+{{x}_{40}}=800\]

\[\Rightarrow \] \[x=800\]

Hence, total age of boys in the class is 800 yr.