I seriously need help I dont get how to solve this question.

Question

An actor invests some money at 6% and $49000 more than four times the amount at 12%, The total annual interest earned from the investment is $70140. How much did he invest at each amount? Use the six-step method.

Answer 1

We have two unknowns, and we can solve this, if we can create two equations.

 

Unknowns:

1. Amount invested at 6%, let's call this X
2. Amount invested at 12%, let's call this Y

 

Our equations:

1. Y=49,000+4X
2. .06X+.12Y=70,140

 

From here, you can use any of your favorite methods for solving equations.  Since equation 1 is already in the form of y=, it's primed for the substitution method.

 

If we plug equation 1 into equation 2, we can solve for X.

 

• .06X+.12(49,000+4X)=70,140
• .06X+5880+.48X=70,140
• .54X=64,260
• X=$119,000

Now we can go back and solve for Y

• Y=49,000+4X
• Y=49,000+4(119,000)
• Y=$525,000

 

Thus we have $119,000 invested at 6% and $525,000 invested at 12%.