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3-117.

You help out at the bowling alley on weekends. One of the arcade games has a bin filled with stuffed animals. A robotic arm randomly grabs a stuffed animal as a prize for the player. You are in charge of filling the bin.

1. You are told that the probability of getting a stuffed giraffe today is $\frac { 2 } { 5 }$. If there are $28$ giraffes in the bin, what is the total number of stuffed animals in the bin?

If $x =$ total stuffed animals:

$\frac{28}{x}=\frac{2}{5}$

2. The next weekend, you see that the bin contains $22$ unicorns, $8$ gorillas, $13$ striped fish, and $15$ elephants. A shipment of stuffed whales arrives. What is the probability of getting a sea animal (whale or fish) if you add $17$ whales to the bin? Express the probability as a percent.

To convert the probability from a fraction to a percent, convert the fraction into a fraction with a denominator of $100$.

3. You are told that the probability of selecting a stuffed alligator needs to be $5\%$. One weekend you notice there are exactly $3$ alligators left. How many total animals should be in the bin to maintain the probability of $5\%$ for an alligator?

If $x=$ total stuffed animals

$\frac{5}{100}=\frac{3}{x}$

$x=60$ animals 