Sandra is 36 years old. Her son is 14 years old. How many years ago was Sandra 3 times older than her son? years ago

36

how many years ago (x years) was sandra (36-x) 3 times as old as son (at that time, 14-x)

sandra's age x years ago is 3 times son's age x years ago

36-x=3 (14-x)

solve

distribute

36-x=42-3x

add 3x both sides

36+2x=42

minus 36

2x=6

divide 2

x=3

3 years ago

(36-3=33, 14-3=11, 11*3=33)