need clarification

[jgmat2010]

A reduction of 20% in the price of mangoes enables a man to buy 25 mangoes more for Rs.40. Find the reduced price of the basket that contains 200 mangoes.


a. Rs. 100 b. Rs. 75 c. Rs. 60 d. Rs. 64 e. Rs. 80

-- so basically it is 8 for 25 mangoes earlier, so for 200 it is 64 and 20% of that should be 51.20 ? but i don't see that answer.

[ace_gre]

Let the cost of a mango be x. Reduced price is 4/5 x. (i.e. 0.8 x)

(40/0.8 x) - (40/x) = 25
10/x = 25
x = 10/25 = 2/5
Cost of 200 mangoes at reduced price of 4/5x = 4/5 * 2/5 * 200 = 64.
IMO D

[papgust]

Let x be the price of a mango and y be the number of mangoes.

Original Price ==> x * y = 40 .... (1)

Reduced Price ==> 0.8x * (y+25) = 40

20x + 0.8xy = 40 ........ (2)

Sub (1) in (2),

20x + 32 = 40
20x = 8
x = 2/5

Sub x in (1) to find y,
y = 100

So, original price per mango is 2/5. Reduced price per mango is 2/5 * 0.8 = 8/25.

The reduced price of the basket that contains 200 mangoes = 8/25 * 200 = 64 (D)