An executive invests $27,000, some at 7% and the rest at 4% annual interest. If he receives an annual return of $1,530, how much is invested at each rate?

Respuesta :

hi

Let's call money invested at 7%  X and the one at  4% Y

So we have :

X+Y = 27 000                       (1)

0.07X + 0.04 Y =  1 530       (2)  

As X+Y = 27 000 then   Y = 27 000 -X

then   we have in line (2)

0.07X + 0.04 ( 27 000 -X) =  1 530

0.07X +  1080 -0.04 X = 1 530

0.07X - 0.04X = 1530 - 1080

          0.03X =  450

                 X = 450 / 0.03

                 X =  15 000

Now  X = 15 000

so Y = 27 000 - 15 000 =  12 000

Answer is :   15 000 dollars were invested at  7% and 12 000 at  4%

Let's check  to be sure  :  

15 000 * 0.07 =  1 050

12 000 *0.04 =     480

and  1 050 + 480 = 1 530