Question

Quadratic equation

Answer 1

Answer:

           46

Step-by-step explanation:

x          -  age of a son three years ago

3x        -  age of a father three years ago

x + 3      -  age of the son now

3x + 3       -  age of the father now

x + 3 + 5       -  age of the son in five years time

3x + 3 + 5       -  age of the father in five years time

in five years time, the father will be twice as old as his son, so:

3x + 3 + 5 = 2(x + 3 + 5)

3x + 8 = 2x + 16

3x - 2x = 16 - 8

  x = 8

x + 3 + 4       -  age of the son in four years time

8 + 3 + 4 = 15

3x + 3 + 4       -  age of the father in four years time

3×8 + 3 + 4 = 31    

the sum of their ages in four years time:

15 + 31 = 46