The initial cost is $45. To determine the increase, you need to follow two steps.
First you have to find what 7% of the original $45 is. This will tell us how much the cost will increase by. To find 7% of $45, you need to multiply .07 x 45 = 3.15 This tells us that 7% of $45 = $3.15
Next, you have to add the increase to the original cost. This will be the new monthly cost. $45 + $3.15 = $48.15