Mary is expected to pay back a total sum of $819200 to her bank as mortgage. If she is expected to make a payment which is double of the previous months amount, how long will it take her to fully repay the loan if her initial payment was $400.	Pick one
A) 13  B) 15  C) 12  D) 10  E) 11
First payment--$400   Total amount to be repaid--$819200   First month payment--$400   Second month payment--$400*2=$800   Third month payment--$800*2  -- 400*2= 
<gadget id="calculator">  -- 400*2</gadget>
<output>800</output>
$800   Third month payment--$800*2=$1600   Fourth month payment--$1600*2 -- 800*2= 
<gadget id="calculator"> -- 800*2</gadget>
<output>1_600</output>
$1600   Fourth month payment--$1600*2=$3200   Fifth month payment--$3200*2  -- 1600*2= 
<gadget id="calculator">  -- 1600*2</gadget>
<output>3_200</output>
$3200   Fifth month payment--$3200*2=$6400   Sixth month payment--$6400*2 -- 3200*2= 
<gadget id="calculator"> -- 3200*2</gadget>
<output>6_400</output>
$6400   Sixth month payment--$6400*2=$12800   Seventh month payment--$25600*2 -- 6400*2= 
<gadget id="calculator"> -- 6400*2</gadget>
<output>12_800</output>
$12800   Seventh month payment--$25600*2=$51200   11ight month payment--$51200*2-- 25600*2= 
<gadget id="calculator">-- 25600*2</gadget>
<output>51_200</output>
$51200   11ight month payment--$51200*2=$102400   Ninth month payment--$102400*2-- 51200*2= 
<gadget id="calculator">-- 51200*2</gadget>
<output>102_400</output>
$102400   Ninth month payment--$102400*2=$204800   Tenth month payment--$204800*2 -- 102400*2= 
<gadget id="calculator"> -- 102400*2</gadget>
<output>204_800</output>
$204800   Tenth month payment--$204800*2=$409600   11leventh month payment--$409600*2 -- 204800*2= 
<gadget id="calculator"> -- 204800*2</gadget>
<output>409_600</output>
$409600   11leventh month payment--$409600*2=$819200   Answer is 11-- 409600*2= 
<gadget id="calculator">-- 409600*2</gadget>
<output>819_200</output>
$819200   Answer is 11
<result>E</result>
Mary is expected to pay back a total sum of $819200 to her bank as mortgage. If she is expected to make a payment which is double of the previous months amount, how long will it take her to fully repay the loan if her initial payment was $400.