Paul invested four times as much money in an account paying $7 \%$ interest than he did in an account paying $1 \%$ interest. If the total interest paid was $\$ 870$, how much did he invest in each?
A) $\$ 120$ at $7 \%$, $\$ 30$ at $1 \%$
B) $\$ 12,000$ at $7 \%, \$ 3000$ at $1 \%$
C) $\$ 12,000$ at $7 \%, \$ 3500$ at $1 \%$
D) $\$ 3000$ at $7 \%, \$ 12,000$ at $1 \%$

Question

Quizplus · Accepted Answer

Let the amount invested at $1\%$ be $x$. Therefore, the amount invested at $7\%$ is $4x$. The total interest from both investments is $0.01x + 0.07(4x) = 870$. Solving this equation gives $x = 3000$ and $4x = 12000$, which matches option B.

Paul Invested Four Times as Much Money in an Account 7%7 \%7%

Paul Invested Four Times as Much Money in an Account $7 \%$