Question

Greg invested $11,000 in two accounts.

• The first account pays 5% interest per year.
• The second account pays 8% interest per year.
• Greg earned a total of $752.50 in interest at the end of the first year.
How much did Greg invest in the 5% account?
A. $6,750
B. $3,415
C. $5,500
D. $4,250

Answer 1

The amount invested in the 5% account is $4,250

Explanation:

Let the amount invested in the first be $x and the amount invested in the second be $y

Total of both is $11,000

Thus, we have

x + y = 11,000 •••••••••(i)

For the first account, the interest earned will be;

5/100 * x = 5x/100 = 0.05x

For the second account , the interest earned will be;

8/100 * x = 0.08x

Adding both gives the total amount of interest

That will be ;

0.05x + 0.08y = 752.50 •••••(ii)

From equation i above;

y = 11,000 - x

Substitute this into ii

0.05x + 0.08(11,000-x) = 752.5

0.05x + 880 - 0.08x = 752.5

0.08x-0.05x = 880-752.5

0.03x = 127.5

x = 127.5/0.03

x = $4,250