Mavis is 5 years older than her brother. Five years ago she was 2 times older than her brother. How old is each now?

15 and 10 because

five years ago he would be 10 and the brother would be 5 and 10 is double 5

M=Mavis

B=Brother Age

M=B+5

Five years ago ...

M-5

B-5

Since Mavis is twice her brother age you have to multiple by 2

(M-5) = 2 (B-5)

Substitute M=B+5

(B+5-5) = 2B-10

B=2B-10

-B=10

10+5=15

Mavis is 15

Brother is 10