Solve the problem using a system of linear equation

Question

Mother is three times as old as her daughter. Ten years from now, Mother will be two times as old as her daughter. How old are they now?

Answer 1

M=3D

M+10 = 2(D+10)

M+10 = 2D +20

M=2D +10

M=3D

3D =2D +10

D =10 years old now, daughter's age

M=30 years old now, mother's age

in 10 years mother will be 40 and daughter 20