Question

Francisco is making popsicles. The popsicle juice starts at 74°F. Once Francisco puts the popsicles in the freezer, they cool at a rate of 9°F per hour. He takes the popsicles out of the freezer when their temperature is below 20°F. How long could Francisco have left them in the freezer?
Solve the associated equation 74 − 9x=20. Show your work on Zearn or solve on paper.
74 − 9x < 20
74−9x
=
20

Answer 1

To find out how long Francisco can leave the popsicles in the freezer while ensuring they cool to a temperature below 20°F, we can start by setting up the equation based on the data provided.

The equation given is:

\[
74 - 9x = 20
\]

### Step 1: Solve the equation

1. **Subtract 74 from both sides**:
\[
74 - 9x - 74 = 20 - 74
\]
This simplifies to:
\[
-9x = -54
\]

2. **Divide both sides by -9**:
\[
x = \frac{-54}{-9}
\]
Simplifying the right side, we get:
\[
x = 6
\]

### Step 2: Interpret the solution

The value of \( x \) represents the number of hours that the popsicles can cool in the freezer before reaching 20°F.

### Conclusion

Francisco can leave the popsicles in the freezer for **6 hours** before their temperature drops below 20°F.

### Step 3: Verify

To verify, we can substitute \( x = 6 \) back into the original equation:

\[
74 - 9(6) = 74 - 54 = 20
\]
This confirms that the calculation is correct, as the temperature exactly equals 20°F at 6 hours.

Thus, the solution stands: **Francisco can leave the popsicles in the freezer for up to 6 hours before the temperature falls below 20°F.**