Question

Able has a younger sister and an older brother. - Able’s age can be represented by x. - Able’s sister is 4 years younger than him. - Able’s older brother is twice as old as he is. - The combined age of all three siblings is 32. How old is Able’s younger sister?

Answer 1

5 years old

Explanation:

Able has a younger sister and an older brother.

Able’s age can be represented by x.

Able’s sister (s) is 4 years younger than him. This can be represented as:

s = x - 4 [1]

Able’s older brother (b) is twice as old as he is. This can be represented as:

b = 2x [2]

The combined age of all three siblings is 32. This can be represented as:

x + s + b = 32 [3]

If we replace [1] and [2] in [3], we get:

x + (x - 4) + 2x = 32

4x = 36

x = 9

The age of Able's younger sister is:

s = x - 4 = 9 - 4 = 5