Question

A biologist studying the relationship between tilapia and catfish in a pond finds that the radio of tilapia to catfish is 6:20. If the pond has 30 catfish, how many tilapia are in the pond?
A. 6
B. 9
C. 10
D. 30

Answer 1

To find the number of tilapia in the pond, we can use the given ratio of tilapia to catfish, which is 6:20.

First, we can simplify this ratio:

\[
\frac{6}{20} = \frac{3}{10}
\]

This means for every 3 tilapia, there are 10 catfish.

Now we know there are 30 catfish in the pond. We can set up a proportion based on the simplified ratio:

\[
\frac{\text{tilapia}}{\text{catfish}} = \frac{3}{10}
\]

Let \( x \) be the number of tilapia. We can set up the equation:

\[
\frac{x}{30} = \frac{3}{10}
\]

Now, we can cross-multiply to solve for \( x \):

\[
10x = 3 \times 30
\]

\[
10x = 90
\]

Now, divide both sides by 10:

\[
x = 9
\]

Therefore, the number of tilapia in the pond is \( 9 \).

The answer is **B. 9**.