Write an equation and solve.

Question

Travis buys a new deep freezer. The manual tells him the temperature will drop 12 degrees every hour after he plugs it in. It is currently 70 degrees in his house. He checks several hours later and the freezer reads -2 degrees. How many hours have passed?

Answer 1

Let's define the variable:

• Let \( h \) be the number of hours that have passed since Travis plugged in the freezer.

According to the problem, the temperature drops by 12 degrees for each hour after plugging in. Thus, the equation representing the temperature in the freezer after \( h \) hours can be expressed as:

\[ \text{Temperature} = \text{Initial Temperature} - (\text{Drop per hour} \times \text{Number of hours}) \]

Given:

• Initial Temperature = 70 degrees,
• Drop per hour = 12 degrees,
• Final Temperature = -2 degrees.

We can set up the equation:

\[ -2 = 70 - 12h \]

Now we'll solve for \( h \).

1. Start by isolating the term with \( h \):

\[ -2 - 70 = -12h \]

\[ -72 = -12h \]

2. Now divide both sides by -12:

\[ h = \frac{-72}{-12} = 6 \]

Thus, the number of hours that have passed is:

\[ \boxed{6} \]