Question

Heather has divided ​$5400 between two​ investments, one paying 8​%, the other paying 5​%. if the return on her investment is ​$345, how much does she have in each​ investment?

Answer 1

Answer:

$2500 at 8%.

$2900 st 5%.

Step-by-step explanation:

Let x be the amount invested at rate of 8% and y be the amount invested at the rate of 5%.

We have been given that Heather has divided ​$5400 between two​ investments. We can represent this information as:

$x+y=5400...(1)$

The return on her investment is ​$345.  

Earnings from the investment at 8% will be 8% of x.

Earnings from the investment at 5% will be 5% of y.

$(\frac{8}{100})x+(\frac{5}{100})y=345...(2)$

$0.08x+0.05y=345...(2)$

We will use substitution method to solve our system of equations. From equation (1) we will get,

$x=5400-y$

Substituting this value in equation (2) we will get,

$0.08(5400-y)+0.05y=345$

$432-0.08y+0.05y=345$

$-0.08y+0.05y=345-432$

$-0.03y=-87$

$\frac{-0.03y}{-0.03}=\frac{-87}{-0.03}$

$y=2900$  

Therefore, Heather has invested an amount of $2900 at 5%.

Let us substitute y=2900 in equation (1) to solve for x.

$x+2900=5400$

$x+2900-2900=5400-2900$

$x=2500$

Therefore, Heather has invested an amount of $2500 at 8%.