Question

The ages of two persons differ by 30 years. If 5 years ago, the elder one was 3 times as old as the younger one, then the present age of the younger person is:

• A. 25 years
• B. 20 years
• C. 30 years
• D. 35 years

Answer 1

Answer:

B. 20 years

Present Age of both are A and B

5 years before

$A-5=3(B-5)$

$A=3B-15+5$

$A=3B-10$

the difference of present age is

$A-B=30$

$3B-10-B=30$

$2B=30+10$

$B=20$

B is the younger person