A certain amount becomes Rs. 5760 in 2 years and Rs. 6912 in 3 years. What is the principal amount and the rate of interest?  Pick:
A) Rs. 3050
B) Rs. 3150
C) Rs. 3450
D) Rs. 4000
E) Rs. 3500
SI on Rs. 5760 for 1 year = 6912 – 5760 = Rs. 1152   Therefore, Rate of interest for 1 year = 100*1152/5760*1= 
<gadget id="calculator">100*1152/5760*1</gadget>
<output>20</output>
20%   Let the principal be p.   Then, Principal= p[1+ 20/100]2 = 5760   Solving which gives Principal = Rs. 4000 ANSWER : Rs. 4000
<result>D</result>
A certain amount becomes Rs. 5760 in 2 years and Rs. 6912 in 3 years. What is the principal amount and the rate of interest?