The sum of Jocelyn and Joseph's age is 40. In 5 years, Joseph will be twice as Jocelyn's present age

The sum of Jocelyn and Joseph's age is 40. In 5 years, Joseph will be twice as Jocelyn's present age. How old are they now?

Let Jocelyn's age be a
Let Joseph's age be b.

We're given two equations:

1. a + b = 40
2. 2(a + 5) = b + 5

We rearrange equation (1) in terms of a to get:

1. a = 40 - b
2. 2a = b + 5

Substitute equation (1) into equation (2) for a:
2(40 - b) = b + 5
80 - 2b = b + 5

To solve this equation for b, we type it in our search engine and we get:
b (Joseph's age) = 25

Now, substitute b = 25 into equation (1) to solve for a:
a = 40 - 25
a (Jocelyn's age) = 15