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?

1 Answer
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:

(d+7)+d=45

d+7+d=45

2d+7=45

2d+77=457

2d=38

2d2=382

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