Skip's

Skip's Dog Shelter rescues collies. 3/4 of the collies are older than 10, and 1/3 of the remaining collies are between 3 and 5. Suppose there are 2 dogs between the ages of 6 and 10. How many dogs are there in all at this rescue shelter?

Correct answer:

n =  12

Step-by-step explanation:

$$\begin{gathered} \frac{3}{4}\cdot n+\frac{1}{3}\cdot (n-\frac{3}{4}\cdot n)+2=n \\ 3/4\cdot n+1/3\cdot (n-3/4\cdot n)+2=n \\ 2n=24 \\ n=\frac{24}{2}=12 \\ n=12 \end{gathered}$$

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