# A pet store currently has a total of 45 cats and dogs. There are 7 more cats than dogs. How do you find the number of cats and dogs in the store?

Nov 20, 2016

In the store there are currently 19 dogs and 26 cats.

#### Explanation:

We are looking for the number of cats and dogs so let's call $c$ the number of cats and $d$ the number of dogs.

Now we are told there are 7 more cats ($c$) than dogs ($d$) so we can write this in mathematical terms as:

$c = d + 7$

We are also told there is a total of 45 cats ($c$) and dogs ($d$). So we can write this as:

$c + d = 45$

We can now substitute, from the first equation, $d + 7$ for $c$ in the second equation and solve for $d$:

$\left(d + 7\right) + d = 45$

$d + 7 + d = 45$

$2 d + 7 = 45$

$2 d + 7 - 7 = 45 - 7$

$2 d = 38$

$\frac{2 d}{2} = \frac{38}{2}$

$d = 19$

Now that we have $d$, or the number of dogs, we can substitute this back into the first equation to calculate $c$, or the number of cats:

$c = 19 + 7$

$c = 26$