Christiana and Marlena opened their first savings accounts on the same day. Christiana opened her account with $50 and plans to deposit $10 every month. Marlena opened her account with $30 and plans to deposit $15 every month.? ... continues in details..

After how many months will their two accounts have the same amount of money? what will that amount be?

1 Answer
Dec 19, 2017

The accounts will have the same amount of money in #4# months.

Explanation:

The first step to solve this question is to get equations for how much money is in Christiana's (C's) and Marlena's (M's) accounts. Then you will set the equations equal to one another because you want to find when they have the same amount of money.

To find the value of C's account, we will start with the information we have. We know that she started with #$50# and is adding #$10# to that amount every month. So the equation for that would be #$50+$10# times the number of months or #50+10m#.

Find the equation for M's account the same way. She starts with #$30# and adds #$15# every month. #$30 + $15# times the number of months. #30+15m#.

Finally, we will set the equations equal to one another. #50+10m=30+15m#. Now you need to get the variables on one side and the constants on the other. If we subtract 30 from both sides you get: #20+10m=15m#. Now subtract #10m# from both sides. #20=5m#. All thats left is to divide by #5#. #4=m#.

So it will be #4# months when they have the same amount of money.