To find the slope representing the monthly cost for the gym membership, we first need to identify the costs for each month and how they grow over time.
The costs given are:
- Month 1: $74
- Month 2: $99
- Month 3: $124
- Month 4: $149
The slope can be found by determining the increase in cost from one month to the next.
Let's calculate the difference in cost month by month:
-
From Month 1 to Month 2:
\(99 - 74 = 25\) -
From Month 2 to Month 3:
\(124 - 99 = 25\) -
From Month 3 to Month 4:
\(149 - 124 = 25\)
The consistent increase in the cost each month is $25.
Now, since the slope represents the monthly cost after accounting for the initial start-up fee, we conclude that the monthly cost (slope) is:
\[ \text{Monthly Cost} = \text{Slope} = 25 \]
Thus, the correct answer is $25.