Lena has $5520 in her bank
she makes $690 monthly payment on a cell phone
Since she is making $690 monthly
In the first month
$5520 - $690 = $4830
The balance after the first withdraw is $4830
For the second month
$4830 - $690 = $ 4140
Third months
$4140 - $690 = $3450
Fourth month
$3450 - $690 = $2760
Fifth month
$2760 - $690 = $2070
Sixth month
$2070 - $690 = $1380
Seventh month
$1380 - $690 = $690
Eigth month
$690 - $690 = $0
Alternatively
We set up an equation
Let the number of month be x
since she is withdrawing $690 every month
$5520 - $690 * x = 0
5520 - 690x = 0
collect the like terms
5520 = 0+ 690 x
690x = 5520
divide both sides by 690
690x / 690 = 5520 / 690
x = 8
The account will be zero after 8 months
The answer is 8
