A man lent out two equal sums in two parts at the rate of 12% and 11% p.a. on simple interest respectively. If the former recovered 3 months earlier than the later and he received equal amount of Rs.15960 each from both the parts. Find the sum.

12000

Note: Principal and amount is same, therefore, simple interest is same in each case.

Therefore, Total Simple Interest = Rate of Interest × Time.

Rate of Interest is inversely proportional to time.

                  I       :      II

Rate  ⇒    12%   :    11%

Time ⇒     11      :     12       ⇒  difference 1R

ATQ,

1R = 3 months

12R = 12 × 3 = 36 months or 3 years.

From the second part total rate of interest received = 11% × 3 = 33%

Hence,

Sum × 133% = Amount = 15960

Sum = \(\frac{15960\;×\;100}{133}\) = 12000