Question

There are thirty-two pets at the pet shop where Donna works. There are three times as many mammals as reptiles in the store. How many reptiles are there at the pet store?A.24B.20C.16D.8

Answer 1

Answer: D. 8

Step-by-step explanation:

Step 1. Given:

There are 32 pets at the shop.

There are 3 times as many mammals as reptiles.

Required: How many reptiles are at the pet store?

Step 2. Since there are three times as many mammals as reptiles, the ratio of mammals to reptiles is:

`\begin{gathered} \text{ratio ma}mmals\text{ to reptiles:} \\ 3\colon1 \end{gathered}`

This means that for every 3 mammals there is 1 reptile.

Step 3. Generalize the ratio for pets and reptiles.

In step three we defined that for every 3 mammals there is 1 reptile, which also means that for every 3+1=4 pets, 1 is a reptile:

`\begin{gathered} \text{Ratio pets to reptiles} \\ 4\colon1 \end{gathered}`

For every 4 pets in the store, 1 is a reptile.

Step 4. Note that the number of reptiles is 1/4 of the number of pets, if the number of pets is 32, the number of reptiles will be:

`(32)/(4)=8`

There are 8 reptiles at the store.

Answer: D. 8