Question

An investment of ​$125,000 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 $9090. 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 1

Let x, y , z be the two three investments.

x+y+z=125,000.

0.08x+0.06y+0.09z=9090.

8x+6y+9z=909000.

0.08x=2*0.06y.

8x=12y.

2x=3y.

By solving above three equations

9x+9y+9z=1125,000

8x+6y+9z=909000. By subtracting

x+3y=216000.

x+2x=216000.

3x=216000.

x=$72000.

y=2*72000/3

y=$48000.

z=125000-72000-48000

z=$5000.