Mr. Kheung had 2,000 dollars to invest. He invested part of it at 5% per year and the remainder at 4% per year. After one year, his investment grew to 2,095 dollars. How much of the original investment was at the 5% rate?
Mr. Kheung had 2,000 dollars to invest. He invested part of it at 5% per year and the remainder at 4% per year. After one year, his investment grew to 2,095 dollars. How much of the original investment was at the 5% rate?
Assuming simple interest
Let the amount invested at 5% per year be represented by X
Let the amount invested at 4% per year be represented by 2,000 – X
The total interest is the final value less the principal which is 2,095 – 2,000 = 95
The total interest is the sum of the two investments
(0.05)(X) + (0.04)(2,000 – X) = 95
Can you take it from there? Solve for X. Go ahead and try. and use the following to check your answer.
(0.05)(X) + (0.04)(2,000 – X) = 95
.05X + 80 – .04X = 95
Combine the X's to get .01X
and subtract 80 from each side .01X = 15
Divide both sides by .01 X = 1500 invested at 5%
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