Let,
Pauls's present age be x.
So his father's age will be 2(x2)
A/Q,
2x2 +10 = 4(x+10)
2x2 + 10 = 4x + 40
2x2 - 4x = 40-10
2x2 -4x = 30
2x2 -4x - 30 = 0
2x2 - 10x + 6x - 30 = 0
2x(x-5) + 6(x-5) = 0
(2x + 6) (x-5) = 0
2x + 6 = 0 or x - 5 = 0
2x = -6 or x = 5
x = -6/2 or x = 5
x = -3 or x = 5
So x = -3, 5
So the age should be in negative value therefore present age of paul is 5 years and his father's age 2(5)2 = 2 x 25 = 50 years.