Investment Math

Question

Please Help. I'm doing 1,000 calculations per second and they're all wrong.

An investor invested a total of ​$2,200 in two mutual funds. One fund earned a 6% profit while the other earned a 2​% profit. If the​ investor's total profit was ​$72, how much was invested in each mutual​ fund?

Answer 1

correct answer is $1500 at 2%

$700 at 6%

scroll to the end to get the correct calculation

but next is a detour into errors

72/2200 = 9/250 = 36/1000 = 3.6% average return

6-3.6 = 2.4

3.6-2 = 1.6

2.4/1.6 = 3/2 ratio of the investments= x/(2200-x)

cross multiply to get

2x = 6600-3x

5x = 6600

x = 1320 invested at 2%

2200-1320 = 880 invested at 6%

1320(.02) + 880(.06) = 26.4 +52.8 = 79.2 which is close to 72 but mistake(s) somewhere

or conventional solution method is:

.02x + (2200-x).06 = 72

-.04x = 72 - .06(2200)

-.04x = 72-132

x = 60/.04 =1500 invested at 2%

2200-1500 = 700 invested at 6%

check the answer

.02(1500)+ .06(700)= 30+42 = 72 Bingo

correct answer is $1,500 at 2%, $700 at 6%