6 times as many

Question

If there are 6 times as  many dogs as cats a d there are 21 total animals how many are dogs? 

Answer 1

let's make our variables d and c for dogs and cats respectively.

Here's what we know:

d + c = 21

6c = d

 

Since we have a value for our variable, let's plug it in:

6c + c = 21

7c = 21

Divide both sides by 7:

c = 3

 

Solve for d:

d = 6 * 3

d = 18

 

Check:

18 + 3 = 21

21 = 21