Mr. Goldstein is 4 times as old as his daughter Anna. In 4 years, he will be 3 times as old as Anna. How old is Anna now?

I know the answer just how did you get your answer?

Lets Anna's age = A

Mr. Goldstein age = G

Mr. Goldstein is 4 times as old as his daughter Anna.

So G = 4A

In 4 years, he will be 3 times as old as Anna

we add 4 with Both their ages

G + 4 = three times of A + 4

G + 4 = 3 (A + 4)

We know G = 4A, replace it in above equation

4A + 4 = 3 (A + 4)

4A + 4 = 3A + 12

Subtract 3A from both sides

A + 4 = 12

Subtract 4 from both sides

A = 8

So Anna's age = 8 years