An investment club invested part of $13,000 at 4% annual interest and the rest at 5%. If the annual income from the investments is $690 and x represents the amount invested at 4%, which expression represents the amount invested at 5%?
A) x + 13,000
B) 690 - x
C) x - 13,000
D) 13,000 - x

Question

Quizplus · Accepted Answer

Let's call the amount invested at 5% "y". Then we know:

x + y = $13,000
0.04x + 0.05y = $690

We can use the first equation to solve for y:

y = $13,000 - x

Then we substitute that into the second equation:

0.04x + 0.05($13,000 - x) = $690

Simplifying:

0.04x + $650 - 0.05x = $690

-0.01x = $40

x = $4,000

So the amount invested at 5% is:

y = $13,000 - $4,000 = $9,000

Therefore, the expression that represents the amount invested at 5% is 13,000 - x, which is equivalent to $9,000.

An Investment Club Invested Part of $13,000 at 4% Annual