Question

Liza is one year older than her sister.

In four years Liza will be three times older than she is now. How old is Liza's sister now?

Answer 1

one-year old

Explanation:

Call Liza L, and her sister S

Liza is one year older.

So L = S + 1

in four years Liza will be three times older.

L + 4 = 3L

4 = 3L - L = 2L

L = 2.

L = S + 1

S = L - 1 = 2 - 1 = 1.