Question 1185278
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If you need to solve 2-part "mixture" problems like this often, and a formal algebraic solution is not required, here is a quick and easy way to solve this kind of problem.<br>
(1) All $19,500 at 4% would yield $780 interest; all at 5% would yield $975 interest.  The actual interest was $940.
(2) Picture the three interest amounts on a number line -- 780, 940, and 975 -- and observe/calculate that 940 is 160/195 of the way from 780 to 975.  That means 160/195 of the total amount was invested at the higher rate.
(3) The numbers work out very nicely in this example; 160/195 of $19,500 is $16,000.<br>
ANSWER: $16,000 was invested at 5%; the other $3,500 at 4%.<br>
CHECK: .05(16000)+.04(3500)= 800+140=940<br>