Question 618292
Let
Present age of Shila = h
Present age of Sanjay = s

Shila is 15 years older than Sanjay
h=s+15............(1)


Ten years after
Shila will be = h+10
Sanjay will be = s+10

Then
Shila will be twice as Sanjay

(h+10)=2(s+10)
h+10=2s+20
h=2s+20-10
h=2s+10...................(2)

Substitute the value of h from (1) to (2)
s+15=2s+10
s-2s=10-15
-s=-5
Cancel out (-)
s=5
Put the value of s in (1)
h=s+15...........(1)
h=5+15
h=20



Present age of Shila = h = 20
Present age of Sanjay = s = 5