Two runners are saving money to attend a marathon. The first runner has $112 in savings, received a $45 gift from a friend, and will save $25 each month. The second runner has $50 in savings and will save $60 each month.

Which equation can be used to find m, the number of months it will take for both accounts to have the same amount of money?

112 - 25m + 45 = 50 - 60m

112 + 25 + 45m = 50m + 60

112 + 25 - 45m = - 50m + 60

112 + 25m + 45 = 50 + 60m

Alright, so we'll have to create two functions ...

The first runner (A) has $112 in savings, received a $45 gift from a friend, and will save $25 each month:

f (m) = 112 + 45 + 25m = 157 + 25m

Now (m) represents time in months (m is a whole number), and f (m) will represent how much money runner (A) has in dollars ($).

Let's turn our attention to the second function ...

The second runner (B) has $50 in savings and will save $60 each month

g (m) = 50+60m

Now (m) represents time in months (m is a whole number), and g (m) will represent how much money runner (B) has in dollars ($).

Now to figure out when both runner (A) and runner (B) will have the same money, we will have to make:

f (m) = g (m)

And this would be the same as saying:

112 + 45 + 25m = 50 + 60m

The correct answer is D.