Question

Dilbert invests a total of $33 000 in two accounts paying 6% and 10\% interest, respectively. How much was invested in each account if, after one year, the total interest was $ 2780?

Answer 1

In the 6% account, 13,000 was deposited

In the 10% account, 20,000 was deposited

Explanation:

Here, we are interested in calculating how much invested in each account

.

Let the amount invested be $x and $y

Mathematically;

x + y = 33,000 ••••(i)

Now let’s work with interest

6% of x + 10% of y = 2780

6/100 * x + 10/100 * y = 2780

Multiply through by 100

6x + 10y = 278000 •••••••••(ii)

From i, x = 33,000 -y

Put this into ii

6(33,000 -y) + 10y = 278000

198,000-6y + 10y = 278000

4y = 80000

y = 80,000/4 = 20,000

But x = 33,000 -y = 33,000 -20,000 = 13,000