Problema Solution
A writer received $43,000 as royalty for her book. She invested part of the money in bonds paying 4% interest annually. The rest she invested in a life insurance policy paying 8% interest annually. If the total interest from the investments after 1 year is $2880, how much did she invest in bonds?
Answer provided by our tutors
nvestment I 6.00% per annum ---x
Investment II 11.00% per annum ---y
x+y=37000 ------------------------1
6.00%x+ 11.00% y=$3,520.00
Multiply by 100
6x+11y= $352,000.00 --------2
Multiply (1) by -6
we get
-6x-6y= -222000.00
Add this to (2)
0 x+ 5y= =$130,000.00
divide by 5
y =$26,000.00 investment at 11.00%
Balance $11,000.00 investment at 6.00%
CHECK
$11,000.00 --------- 6.00% ------- $660.00
$26,000.00 ------- 11.00% ------- $2,860.00
Total -------------- $3,520.00