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Ok guys here is my question, from the topscore pro software, test one, math question 19.
Mark has $7200 invested, part at 4% and the rest at 5%. if the annual income from both investments is the same, what is the income from his investment?
The answer is below:
Let x = principle amt invested at 4%
let 7200 - x = principle amt invested at 5%
principle x rate = income
.04x = .05 (7200-x)
9x = 5(7200)
x=4000
4000 x .04 = income
income = 160
total = 160 x 2 = 320
I get all of the above, EXCEPT for where the 9x = 5(7200) is coming from. I know it's probably some simple calculation, but I am not seeing it for the life of me, and my test is in 2 days! crap!!!!!! I also do not understand how the -x has magically disappeared after the 7200.
anyways, I would appreciate any explanation for this, the topscore software doesn't do that great of a job explaning how it gets to certain conclusions/answers.
thanks in advance!
Mark has $7200 invested, part at 4% and the rest at 5%. if the annual income from both investments is the same, what is the income from his investment?
The answer is below:
Let x = principle amt invested at 4%
let 7200 - x = principle amt invested at 5%
principle x rate = income
.04x = .05 (7200-x)
9x = 5(7200)
x=4000
4000 x .04 = income
income = 160
total = 160 x 2 = 320
I get all of the above, EXCEPT for where the 9x = 5(7200) is coming from. I know it's probably some simple calculation, but I am not seeing it for the life of me, and my test is in 2 days! crap!!!!!! I also do not understand how the -x has magically disappeared after the 7200.
anyways, I would appreciate any explanation for this, the topscore software doesn't do that great of a job explaning how it gets to certain conclusions/answers.
thanks in advance!
