Question

The Greens want to put an addition on their house 18 months from now. They will need to save $10,620 in order to achieve this goal. They set aside the same amount each month, and after a year discover they have saved $6,120. The Greens must adjust their plan in order to meet their goal, so they came up with the following options: Option A: Stay with saving the original amount each month but put the addition on one month later than originally planned. Option B: Increase the amount of money they save each month by $120 from their original plan. Which of the following statements is true?

Answer 1

The easiest of the two options to prove is option A.

To see whether or not option A. is true, we need to find out how much the Greens have been saving every month. We know that the Greens have saved $6120 in the last year, or twelve months. To find out how much they have been saving each month, we need to divide the amount they have saved by the number of months they have been saving.

$6120/12 months

This turns out to be $510 each month.

Now, to find out whether or not option 11
A. is true, we need to find out the amount of money that the Greens would save in eighteen months.

$510 * 18 = $9180

Now that we have the amount of money that the Greens would save over eighteen months, we need to see if an additional month of saving would let them reach $10,620.

$9180 + $510 = $9690

Now, we know that option A is not true because the Greens would not have enough money after only one extra month of saving. Because option A is not true, option B must be true.