Problema Solution
An investment of
$35,000
was made by a business club. The investment was split into three parts and lasted for one year. The first part of the investment earned 8% interest, the second 6%, and the third 9%. Total interest from the investments was
$2610.
The interest from the first investment was
2
times the interest from the second. Find the amounts of the three parts of the investment
Answer provided by our tutors
Let x, y, z be the three investments that earned 8%, 6%, and 9% interest respectively.
The total money invested was $35,000 means:
x+y+z=35,000
The total interest earned was $2,610:
0.08x+0.06y+0.09z=2610 multiply both sides by 100
8x+6y+9z=261000
The interest from the first investment equals 2 times the interest of the second:
0.08x=2*0.06y multiply both sides by 100
8x=12y divide both sides by 4
2x=3y
We have the following system of three equations:
x+y+z=35000
8x+6y+9z=261000
2x=3y
.......
click here to see the system of equations solved for x, y and z
........
x = $18,000
y = $12,000
z = $5,000
$18,000 were invested at 8%, $12,000 were invested at 6% and $5,000 were invested at 9%.