an executive invests 2700 some at 7% and some at 4% annual interest. If he receives an annual return of 1,560, how much is invested at each rate?

Question

I need to know the rate invested.

Answer 1

I will presume that the figure 1560 was merely a typographical error, and that the number $156 was meant.

If so, then let x = dollar amount invested at 7% (as a decimal, 0.07)

Then $2700 - x = dollar amount invested at 4% (as a decimal, 0.04)

we know that Interest = Principal x Rate x Time (in this case, T = !)

Our equation becomes $156 = 0.07x + ($2700 - x)0.04

then, $156 = 0.07x + $108 - 0.04x

combining, we get $48 = 0.03x

solving, x = $1600, which is the amount invested at 7%

then $2700 - 1600 = $1100, which is the amount invested at 4%

 

Proof: $1600 x 0.07 + $1100 x 0.04 = $112 + $44 = $156

Answer 2

are you sure the annual return is 1560 not 156?