When there is 12.5% fall in price of a chocolate bar, a person is able to purchase 40 more in Rs. 800. The cost (in Rs) of 100 chocolate bars at reduced price is:
Let the initial price of chocolate bar =Rs. x and Number=n
Then, x*n = 800
Also, 0.875x*(n+40) = 800
⇒ 0.875x*n + 35x = 800
0.875*800 + 35x = 800
x = 20/7
Cost of 100 chocolate bar at reduced price = 100*0.875*(20/7) = 250
Correct Option 9)