Vinny is 5years older than his sister Lucy. Lucy is y years old now. Write an expression to show the sum of their ages in 10years to come.
Lucy's present age ---- y
Vinny's present age = y+5
10 years from now:
Lucy's age = y+10
Vinny's age = y+5 + 10 = y + 15
at that time, sum of their ages = y+10 + y+15 = 2y + 25