Survey of Math 140
posted by JrUNCFan on .
on march 8, you sign a $4000 note with simple interest 10% for 240 days. You make partial payments of $1300 on May 26 and $2300 on july 31. How much will you owe on the date of maturity (November 3)?
Please show work!!!

First calculate the number of days between March 8 and May 26. 24 days in March, 30 days in April, and 26 days in May. Add those together=80 days.
4000(1+.10)^(80/365)= 4084.44. This is how much you owe on May 26, before the $1300 payment.
Then subtract 4084.441300. This is your new balance. 2784.44
Now calculate the days between May 26 and July 31. 4 days in May, 30 in June, 31 in July. This is 65 days.
2784.44(1+.10)^(65/365)=2832.10 This your balance on July 31st before making payment. Now subtract 2300. 2832.102300=532.10 Now calculate the number of days between July 31st and November 3rd=95 days.
532.10(1+.10)^(95/365)=545.46. This is how much you owe on November 3rd. 
545.46 is not one of the choices that i have to choose from. the choices are 553.11, 555.05, 544.98, and 557.88

sorry. you could try changing the 80 to 79 in the first part. I was debating with myself, which one to use.

Simple interest
10% = 0.1 /365 = 0.000274 daily interest
3/8 to 5/26 = 79 days
79 * 0.000274 = 0.021646 (79 day interest rate) * $4000 = $86.58 interest this period
5/27 to 7/31 = 65 days
65 * 0.000274 = 0.01781 (65 day interest rate) * $2700 ($4000  1300) = 48.08 interest this period
8/1 to 11/3 = 94 day
94 * 0.000274 = 0.025757 (94 day interest rate) * $400 $2700  2300) = $10.30 interest this period
Payment on 11/03 $400 + interest =
$400.00 + 86.58 + 48.08 + 10.30 = 544.96 
convert the numeral to a numeral in base ten
43,163ten