Question 1135999
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Here is an alternative to the standard algebraic solution method suggested by the other tutor.<br>
This problem is essentially a mixture problem -- you are mixing investments at 4% and 6% and getting an overall percentage return somewhere between 4% and 6%.<br>
This method for solving mixture problems is based on the fact that how the investment is split between the two percentages exactly determines the overall interest rate.<br>
(1) $35000 all at 4% would provide $1400 interest; all at 6% would provide $2100 interest.
(2) The actual amount of interest, $1800, is 4/7 of the way from $1400 to $2100.  (2100-1400 = 700; 1800-1400 = 400; 400/700 = 4/7)<br>
(3) That means 4/7 of the total was invested at the higher rate.<br>
ANSWER: 4/7 of $35,000 = $20,000 at 6%; 3/7 of $35,000 = $15,000 at 4%.<br>
CHECK: .06(20,000)+.04(15,000) = 1200+600 = 1800