could someone help me with math?

Question

Suppose you invest money in two accounts. One of the accounts pay 10% annual interest, whereas the other pays 11% annual interest. If you have $5,000 more invested at 11% than you invested at 10%, how much do you have invested in each account if the total amount of interest you earn in a year is $1,390?

 

You are investing $________ at 10% and $_______at 11%

Answer 1

Good morning Jay,

 

Let's set up this question with what we know.

X = amount invested in account paying 10% annual interest

Y = amount invested in account paying 11% annual interest

 

From the 3rd sentence

Y = X + 5000

.1X + .11Y = 1390

 

Let's substitute Y=X+5000 for Y in the last equation.

.1X + .11Y = 1390

.1X + .11(X+5000) = 1390

 

Distribute

.1X + .11X + 550 = 1390

 

Combine terms

.21X +550 = 1390

 

And solve for X

.21X = 840

X = 4000

Y = 4000+5000 = 9000

 

You are investing $4,000 at 10% and $9,000 at 11%.