A man invests Rs. 7,000 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?	Choose the correct choice from the following answers
A) Rs. 1200
B) Rs. 1300
C) Rs. 3500
D) Rs. 2000
E) None of these
Explanation :   Interest on Rs.7000 at 5% per annum = ( 7000 × 5 × 1) / 100 = Rs. 350   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 = (7000 + x) × 6 × 1/100.   =&gt; 350 + 2x/25 = (7000 + x) × 6 × 1/100.   =&gt; 35000 + 8x = (7000 + x) × 6.   =&gt; 35000 + 8x = 42000 + 6x.   =&gt; 2x=7000.   =&gt; x=3500.   Answer : Rs. 3500
<result>C</result>
A man invests Rs. 7,000 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?