Question

If A's age and B's age are in the ratio 2:1, and if A's age = 20 years, then B's age = ____.

• A. 40
• B. 10
• C. 5
• D. 15

Answer 1

The correct option is B

10

A's age:B's age = 2:1
$\Rightarrow$ 20:B's age = 2:1
$\Rightarrow$ 20/B's age = 2/1
$\Rightarrow$ B's age = 20/2
$\Rightarrow$ B's age = 10

Therefore, B's age is 10 years.