Question

Mr. Jackson invested a sum of money at 6% per year, and 3 times as much at 4%

per year. How much did he invest at each rate if his annual return totaled $144?

Answer 1

Mr. Jackson invested $800 at 6% per year and $ 2400 at 4 % per year

Solution:

Mr. Jackson invested a sum of money at 6% per year, and 3 times as much at 4% per year.

Let the sum invested be ‘a’ and ‘3a’ at 6% per year and 4 % per year respectively

Also, his annual return totaled $144

We can form following equation on the basis of question:-

`\begin{array}{l}{\text { Then, } (a * 6 * 1)/(100)+(3 a * 4 * 1)/(100)=\$ 144} \\\\ {(6 a)/(100)+(12 a)/(100)=144} \\\\ {(6 a+12 a)/(100)=144} \\\\ {(18 a)/(100)=144} \\\\ {18 a=14400} \\\\ {a=14400 / 18}\end{array}`

a = $800

The amount of money invested at 6% = a = 800

The amount of money invested at 4 % = 3a = 3(800) = 2400

So, the amount of money invested at 6% is $800 and the amount of money invested at 4% is $ 2400