Answer to Question #327648 in Algebra for Duncan

Question

Carl and Dennis are brothers. The sum of their ages is 29. In 6 years' time Carl will be the same age as Dennis was 3 years ago.

Answer 1

Let Carl be "x" years old

Let Dennis be "y" years old

Then,

$\begin{cases} x + y = 29 \\ x + 6 = y - 3 \end{cases} \begin{cases} x + y = 29 \\ x - y = - 9 \end{cases} +$

$2x = 20 \\ x = 10$

Then

$y = 29 - 10 \\ y = 19$

Answer:

Carl is 10 years old

Dennis is 19 years old