Answer:
Explanation:
At present:
Let son's age = x
Father's age = 2x + 10
Before 20 years:
son's age = x - 20
Father's age = 2x + 10 - 20 = 2x - 10
Father's age = 5 * (Son's age)
2x - 10 = 5*(x - 20)
2x - 10 = 5x - 100 {add 100 to both sides}
2x -10 + 100 = 5x - 100 +100
2x + 90 = 5x {Subtract 2x from both sides}
2x + 90 - 2x = 5x- 2x
90 = 3x {divide both sides by 3}
90/3 = x
x = 30
Present age of :
Son = 30 years
Father = 2*30 +10 = 60 + 10
= 70 years