Roy is twice as old as Joan. In 3 years the sum of their ages will be 21. How old are they now?

Answer 1

Let x = Joan's age

Let 2x = Roy's age

x + 3 = Joan's age in 3 years

2x + 3 = Roy's age in 3 years

x + 3 + 2x + 3 = 21

3x + 6 = 21

3x = 15

x = 5 years

2x = 10 years

Answer 2

j represents Joan's age today

2j represents Ryan;s age today

j + 3 represents Joan's age in 3 years

2j + 3 represents Ryan's age in 3 years

j + 3 + 2j + 3 = 21

Can you solve for j and answer?