72 hens cost Rs. __ 96.7__. Then what does each hen cost, where two digits in place of ‘__’ are not visible or are written in illegible hand?  Select the correct option
A) Rs. 3.23
B) Rs. 5.11
C) Rs. 5.51
D) Rs. 7.22
E) None
Explanation :   The best way to solve this question is to multiply the alternatives by 72 and find which one gives the middle three digits 96.7.   To cut time, you can choose to multiply 72 by integer values only, e.g. 72 × 3 = 216, 72 × 5 = 360 and 72 × 7 = 504.   It must be remembered that the decimal part of the answer will be multiplied by 72 and the actual answer will increase .   Let us now roughly multiply the decimal values of the options also by 72,   e.g. 72 x 0.2 = 14.4, 72 × 0.1 = 7.2 and 72 × 0.5 = 36.   So, option (1) will yield (216 + 14)= 
<gadget id="calculator">(216 + 14)</gadget>
<output>230</output>
230 (approximately),   option(2) will yield (360 + 7)= 
<gadget id="calculator">(360 + 7)</gadget>
<output>367</output>
367 (approximately),   option(3) will yield (360 + 36)= 
<gadget id="calculator">(360 + 36)</gadget>
<output>396</output>
396 (approximately),   and option(4) will yield (504 + 14)= 528 (approximately).   Of these only option (3) satisfies our requirement of 2nd and 3rd digits being 96.   Answer : Rs. 5.51
<result>C</result>
72 hens cost Rs. __ 96.7__. Then what does each hen cost, where two digits in place of ‘__’ are not visible or are written in illegible hand?