Question 635660
Let
Present age of One = a
Present age of Other = b

Sum of the age is 20
a+b = 20 .................(1)

In Fiver years
One will be = a+5 years old
Other will be = b+5 years old
Then
One is twice the other
a+5=2(b+5)
a+5=2b+10
a=2b+10-5
a=2b+5......................(2)
Put the value of a in (1)
2b+5+b = 20
3b+5=20
3b=20-5
3b=15
3b/3=15/3
b=15
Put the value of b in (1)
a+b=20.........(1)
a+15=20
a=20-15
a=5


Present age of One = a = 5 years old
Present age of Other = b = 15 years old