Question

Robert's dog is 4 years older than Karen's cat. In 3 years, the sum of the ages of Robert's dog and Karen's cat will be 13. How old is Robert's dog right now?

Answer 1

Answer:

5.5 years old.

Step-by-step explanation:

Let D represent present age of Robert's dog and C represent present age of Karen's cat.

We have been given that Robert's dog is 4 years older than Karen's cat. We can represent this information in an equation as:

$D=C+4...(1)$

We are also told that in 3 years, the sum of the ages of Robert's dog and Karen's cat will be 13. After 3 years age of dog and cat would be $D+3$ and $C+3$ respectively.

We can represent this information in an equation as:

$D+3+C+3=13...(2)$

From equation (1), we will get:

$C=D-4$

Upon substituting this value in equation (2), we will get:

$D+3+D-4+3=13$

Combine like terms:

$2D+2=13$

$2D+2-2=13-2$

$2D=11$

$\frac{2D}{2}=\frac{11}{2}$

$D=5.5$

Therefore, Robert's dog is 5.5 years old right now.