Question

Kelly invested her savings of $4800. she invested part in mutual funds, at 9% per year, and the rest in GIC's, at 10% per year. at the end of the year, the interest from both investments is $457. how much did she invest at each rate?

Answer 1

For the 9% she invested $2,300

For the 10% she invested $2,500

Explanation:

Let the amount invested be $x and $y in both cases respectively

Since the total invested is $4,800

This means that;

x + y = 4800 ••••••••••••(i)

Now let’s have a look at the interests.

For the 9%

Interest would be 9/100 * amount invested

= 9/100 * x = 9x/100

For the 10%, interest would be

10/100 * y = 10y/100

Adding both will give a total of 457

9x/100 + 10y/100 = 457

multiply through by 100

9x + 10y = 45700 •••••••• (ii)

From equation i, we can write x = 4800 - y

we can substitute this into the second equation

9(4800-y) + 10y = 45700

43200 -9y + 10y = 45,700

43200 + y = 45,700

y = 45,700-43,200 = $2,500

Recall

x = 4800 -y

so x = 4800 -2500 = 2300