In a pet store there are 4 more cats than dogs and the ratio of cats to dogs is 12 to 9.What is the total number of cats and dogs in the pet store?

1 answer

let the number of cats be 12x
let the number of dogs be 9x

12x - 9x = 4
3x=4
x = 4/3

number of cats = 12x = 12(4/3) = 16
number of dogs = 9(4/3) = 12
for a total of 28 cats and dogs.

check:
16:12 = 4:3 or the given 12:9
cats - dogs = 16-12 = 4 , thus 4 more cats than dogs