An investment of $80,000 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% interest from the investments was $6120. The interest from the first investment was 2 times the interest from the second. Find the amounts of the three parts of the investment.
Write a linear system of equations. Let $x$ be the first investment, $y$ be the second investment, and $z$ be the third investment. Choose the correct answer below.
A. $x + y + z = 2(0.06y)$
$0.08x + 0.06y + 0.09z = 6120$
$0.08x = 80,000$
C. $x + y + z = 6120$
$0.08x + 0.06y + 0.09z = 80,000$
$0.08x = 0.06y$
B. $x + y + z = 80,000$
$0.08x + 0.06y + 0.09z = 6120$
$0.06x = 2(0.08y)$
D. $x + y + z = 80,000$
$0.08x + 0.06y + 0.09z = 6120$
$0.08x = 2(0.06y)$
The club invested $\boxed{}$ at 8%, $\boxed{}$ at 6%, and $\boxed{}$ at 9%.
