Question

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 ?

Answer 1

Remark:

12 = 4 * 3

9 = 3 * 3


12 / 9 = 4 * 3 / ( 3 * 3 ) = 4 / 3

________________________________________



C = number of cats

D = numbers of dog


C = D + 4


C / D = 12 / 9

C / D = 3 * 4 / ( 3 * 3 )

C / D = 4 / 3


________________________________________

In a pet store there are 4 more cats than dogs.

That mean C = D + 4

________________________________________

C / D = 4 / 3

( D + 4 ) / D = 4 / 3 Multiply both sides by 3

3 ( D + 4 ) / D = 4 * 3 / 3

( 3 D + 12 ) / D = 4 Multiply both sides by D

( 3 D + 12 ) * D / D = 4 D

3 D + 12 = 4 D Subtract 3 D to both sides

3 D + 12 - 3 D = 4 D - D

12 = D

D = 12


C = D + 4

C = 12 + 4 = 16


16 Cats and 12 dogs.


The ratio of cats to dogs:

C / D = 16 / 12 = 4 * 4 / ( 4 * 3 ) = 4 / 3

Answer 2

It means that if there are 4 cats in the store there are 5 dogs, if there are 8 cats (4×2) there then there will be 10 dogs (5×2)