Question

Four years from now Emily will be as old as Cathy is now. Seven years ago, the sum of their ages was 22. Write a system of equations to model this situation and solve it using substitution to determine how old the girls are now.

Answer 1

e+4=c
e-7 +c-7 = 22

e - c = -4
e + c = 36
-------------- add
2 e = 32
so
e = 16
then c = 20