Question

Roberto invested a total of $10,000, part at 6% and part at 9%. How much did he invest in the HIGHER interest account if the total interest earned in one year was $810?

Answer 1

Given :

Roberto invested a total of $10,000, part at 6% and part at 9%.

To Find :

How much did he invest in the higher interest account if the total interest earned in one year was $810 .

Solution :

Let , x amount is invested in 6% interest .

Therefore , 10000-x amount is invested in 9% interest .

Now , total interest is $810 .

We know , simple interest is given by :

$I=\dfrac{PRt}{100}$

So ,

$\dfrac{x(1)(6)}{100}+\dfrac{(10000-x)(1)(9)}{100}=810$

Solving above equation , we get :

$x=\ 3000$ .

Therefore , investment on higher i.e 9 % is 10000-3000 = $7000 .

Hence , this is the required solution .