Q10 of 40 Page 92

Suppose you have D12000 to save. You have to save some amount at 10% and the rest at 15%. How much should be saved at each rate to yield 12% on the total amount saved?

Let the amount be invested at 10% be x and amount to be invested at 15% be y.

Total amount to be invested is ₹12000


Therefore, x + y = 12000 …I


Simple interest on ₹x at 10% for 1 year =


Simple interest on ₹y at 15% for 1 year =


Now, total amounts is to be invested at 12%


=



2x + 3y = 28800 …II


Multiplying Eq. I by 2 and solving with Eq. II


2x + 3y = 28800


2x + 2y = 12000


_- - - _


y = 4800


substitute y = 4800 in Eq. I


x + 4800 = 1200


x = 7200


Hence the amount to be invested at 10% is ₹7200 and the amount to be invested at 15% is ₹4800.


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