Question

if i am 3 times as old as my sister and last year i was 4 times as old as her how old am i now and how old is she


well how old is your sister


You are 9 and she is 3 (3x3=9)
Last year you were 8 and she was 2
(2x4=8)

your sister is 3 and you are 9

let x = sister's age
and y = your age.
================
last year sister's age was x-1.
last year your age was y-1.

y = 3x for this year.
y-1 = 4(x-1) for last year.
solve for x and y.

The answers above are correct but this tells you how to do it.