sunita is 5year older than kavita the sum of thair age after 10 year will be 55year their present age is kavita 15 year and sunita 20 year how?

How what? I'm guessing at what you want.

Let x = Kavita's age, then x+5 = Sunita's.

x + 10 + x + 5 + 10 = 55

Solve for x.

2x = 30

x = 15