Question

Edy has 450$ in her savings account. She deposits 40$ each month. Juan has 975$ in his checking account. He writes a check for 45$ each month for his cell phone bill. He also writes a check for 20$ each month for his water bill. After how many months will Edy and Juan have the same amount of money in their accounts?

Answer 1

Edy and Juan have the same amount of money in their accounts after 5 months.

Explanation:

Edy

saving account = $450

She deposits $40 each months, so

credits = $40 per month

Juan

saving account = $975.

he have to pay $45 for cellphone bill and $ 20 for water bill each month, Therefore

Debits = $45 + $20

= $65

let say after M months, the total money of both will be the same. to find the M, first, we can calculate the amount of money each of them.

The amount of Edy's money in her saving account can be calculated by adding the money in her saving account and her deposits ($40) in M months, as below

Edy's Money = $450 + ($40 x M)

The amount of Juan's money is the subtraction of his saving account and the total of bill payments in M months.

Juan's Money = $975 - ($65 x M)

The money of Both Edy and Juan after M month is the same, hence

Edy's Money = Juan's Money

$450 + ($40 X M) = $975 - ($65 x M)

Move $450 to the right which will be in minus, and move ($65 x M) to the left side which will be plus.

Notes : moving subtraction or addition to the other side will change their symbol, plus become minus and minus become plus.

($40 X M) + ($65 x M) = $975 - $450

M x ($40+$65) = $525

M x ($105) = $525

M =
`(525)/(105)`

M = 5