Question

Mary is three years older than Ned and two years younger than Carla. Ten years ago, Carla’s age was equal to the sum of the ages of Ned and Mary. How old is each now?

Answer 1

Let x be Mary’s age

Let x-3 be Ned’s age

Let x+2 be Carla’s age

(x+2)-10=(x-10)+[(x-3)-10]

x+2-10=x-10+x-3-10

x-x-x=-10-3-10-2+10

-x=-15

x=15

Mary is 15, Ned is 12, and Carla is 17.