To find out how many times Joyce needs to visit the zoo to justify the membership fee, we can set up the following equations:
- The cost of visiting the zoo without a membership for \( x \) visits: \( 45x \)
- The cost of visiting the zoo with a membership for \( x \) visits: \( 50 + 20x \)
We want to find the point at which these costs are equal:
\[ 45x = 50 + 20x \]
Now, let's solve for \( x \):
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Subtract \( 20x \) from both sides: \[ 45x - 20x = 50 \] \[ 25x = 50 \]
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Divide both sides by 25: \[ x = \frac{50}{25} \] \[ x = 2 \]
So, Joyce will need to visit the zoo 2 times to justify the expense of the membership fee.
The correct response is: 2