Question

Matthew is 7 years older then twice the age of his sister. If Matthew is 13, how old is his sister? (NOT SUBTRACTION,ITS MUCH MORE)

Answer 1

S = sisters ages

M =2S +7

M=13

13 = 2S+7

subtract 7 from each side

6 = 2S

divide by 2

3=S

sisters age is 3