SOLUTION: To buy both a new car and a new house, Tina sought two loans totalling $191,610. The simple interest rate on the first loan was 6.3%, while the simple interest rate on the second l

Algebra ->  Expressions-with-variables -> SOLUTION: To buy both a new car and a new house, Tina sought two loans totalling $191,610. The simple interest rate on the first loan was 6.3%, while the simple interest rate on the second l      Log On


   



Question 548945: To buy both a new car and a new house, Tina sought two loans totalling $191,610. The simple interest rate on the first loan was 6.3%, while the simple interest rate on the second loan was 8.8%. At the end of the first year, Tina paid a combined interest payment of $16,681.66. What were the amounts of the two loans?
How do I set up and answer

Found 2 solutions by mananth, josmiceli:
Answer by mananth(16946) About Me  (Show Source):
You can put this solution on YOUR website!
Fund A 6.30% per annum ---x
Fund B 8.80% per annum ---y

x+y=191610 ------------------------1
6.30%x+ 8.80%y= =$16,681.66
Multiply by100
6.3x+8.8y=$1,668,166.00 --------2

Multiply (1) by -6.3
we get

-6.3x-6.3y=-1207143.00

Add this to (2)

0x+2.5y=$461,023.00

divide by2.5

y = $184,409.20 investment at 8.80%
Balance $7,200.80 investment at 6.30%
CHECK
$7,200.80 --------- 6.30% ------- $453.65
$184,409.20 ------- 8.80% ------- $16,228.01
Total -------------- $16,681.66
m.ananth@hotmail.ca



Answer by josmiceli(19441) About Me  (Show Source):
You can put this solution on YOUR website!
The formula for simple interest is
+A+=+P%2A%28+1+%2B+t%2Ar+%29+
+A+ = amount after t years
+P+ = original amount
+r+ = annual % interest rate
----------------------------------
Let the equation for the 1st loan be
+A%5B1%5D+=+P%5B1%5D%2A%28+1+%2B+t%2Ar%5B1%5D+%29+
Let the equation for the 2nd loan be
+A%5B2%5D+=+P%5B2%5D%2A%28+1+%2B+t%2Ar%5B2%5D+%29+
given:
+r%5B1%5D+=+.063+
+r%5B2%5D+=+.088+
+P%5B1%5D+%2B+P%5B2%5D+=+191610+
and
Adding the 2 equations with +t+=+1+

+A%5B1%5D+%2B+A%5B2%5D+=+191610+%2B+.063P%5B1%5D+%2B+.088P%5B2%5D+
The combined interest payment is
(1) +.063P%5B1%5D+%2B+.088P%5B2%5D+=+16681.66+
But also
(2) +P%5B1%5D+%2B+P%5B2%5D+=+191610+
Multiply both sides of (2) by +.063+
and subtract (2) from (1)
(1) +.063P%5B1%5D+%2B+.088P%5B2%5D+=+16681.66+
(2) -.063P%5B1%5D+-+.063P%5B2%5D+=+-12071.43+
+.025P%5B2%5D+=+4610.23+
+P%5B2%5D+=+184409.2+
and,
(2) +P%5B1%5D+%2B+184409.2+=+191610+
(2) +P%5B1%5D+=+191610+-+184409.2+
(2) +P%5B1%5D+=+7200.8+
The amounts of the loans were:
$7,200.80 @ 6.3%
$184,409.20 @ 8.8%
check:
+A%5B1%5D+=+P%5B1%5D%2A%28+1+%2B+.063+%29+ ( t = 1 )
+A%5B2%5D+=+P%5B2%5D%2A%28+1+%2B+.088+%29+
+A%5B1%5D+=+7200.8%2A%28+1+%2B+.063+%29+
+A%5B2%5D+=+184409.2%2A%28+1+%2B+.088+%29+
+A%5B1%5D+=+7654.45+
+A%5B2%5D+=+200637.21+
The combined interest payment should be

+208291.66+-+191610+
+16681.66+ This is correct