Question

David is 38 years old and his son Frank is

8. In how many years will David be twice
as old as Frank?
a) Define a variable:
b) Write an equation.
C) Solve the equation./
d) Answer what is being asked in a
complete sentence.

Answer 1

a. Let the variable be x

b. 38 + x = 2(8 + x)

c. x = 22

d. In 22 years time, David will be twice as old as Frank

Explanation:

a. Let the number of years be x

b. In x years time, David will be 38 + x while Frank will be 8 + x

Also in x years time, 38 + x will be two times 8 + x

Mathematically;

38 + x = 2(8 + x)

c. 38 + x = 2(8 + x)

38 + x = 16 + 2x

38-16 = 2x - x

x = 22

d. In 22 years time, David will be twice as old as Frank