A man invests Rs. 8,000 at the rate of 5% per annum. How much more should he invest at the rate of 8%, so that he can earn a total of 6% per annum?
Pick one.
A) Rs. 1200
B) Rs. 1300
C) Rs. 1500
D) Rs. 4000
E) None of these
Explanation :   Interest on Rs.8000 at 5% per annum = ( 8000 × 5 × 1) / 100 = Rs. 400   Let his additional investment at 8% = x   Interest on Rs.x at 8% per annum = ( x × 8 × 1 ) / 100 = 2x/25.   To earn 6% per annum for the total, interest = (8000 + x) × 6 × 1/100.   =&gt; 400 + 2x/25 = (8000 + x) × 6 × 1/100.   =&gt; 40000 + 8x = (8000 + x) × 6.   =&gt; 40000 + 8x = 48000 + 6x.   =&gt; 2x=8000.   =&gt; x=4000.   Answer : Rs. 4000
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A man invests Rs. 8,000 at the rate of 5% per annum. How much more should he invest at the rate of 8%, so that he can earn a total of 6% per annum?