A father's age is seven times that of his son's age. After three years, the father's age will be five times that of his son's age. What is the father's current age?

The father's current age is seven times the son's current age.

After three years, the father's age will be five times the son's age.

Let the son's current age be x years.
Then the father's current age is:7x years 

After 3 years:

The son's age will be: x + 3 years.

The father's age will be: 7x + 3 years.

According to the condition,

7x + 3 = 5(x + 3)

7x + 3 = 5x + 15

7x - 5x = 15 – 3

2x = 12

2x = 12

x = 6

The father's age is 7x:

7x = 7(6) = 42 years