Question 1208045
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Mr B invested p30000:part at 5% and part at 8%.
The total interest on the investment was p2100. How much did she invest at each rate.
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x         invested at 8%;
(30000-x) invested at 5%.


The total annual interest is 0.08x + 0.05(30000-x).


An equation to find x is

    0.08x + 0.05(30000-x) = 2100.


Simplify and find x

    0.08x + 1500 - 0.05x = 2100

    0.08x - 0.05x = 2100 - 1500

         0.03x    =     600

             x    =     600/0.03 = 20000.


<U>ANSWER</U>.  p20000 invested at 8%.  The rest,  p30000 - p20000 = p10000 invested at 5%.


<U>CHECK</U>.   0.08*20000 + 0.05*10000 = 2100 for the total annual interest.   ! precisely correct !
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Solved.