Problema Solution
An investment of $98,000, was made by a business club. The investment was split into three parts and lasted for one year. The firs part of the investment earned 8% interest, the second 6%, and third 9%. Total interest from the investments was $7620. The interest from the first invesment was 6 times the interest from the second. Find the amounts of the three parts of the investment.
Answer provided by our tutors
Total interest = $ 7620
Let the 1st part of investment be x, 2nd part be y and 3rd part be z.
So, 0.08x+0.06y+0.09z = 7620
The interest from the first invesment was 6 times the interest from the second.
SO, 0.08x = 6*0.06y; => x = 0.36/0.08 y = 4.5y
Therefore: 6*0.06y+0.06y+0.09z = 7620 ==> 0.42y+0.09z = 7620; and x+y+z = 98000;
Substitute the value of x ==> 4.5y+y+z = 98000 => 5.5y+z = 98000;
Solving two equations in y and z by substitution method: y = 16000 ;
So, x = 4.5y = 72000;
So, z = 98000-(x+y) = 10000