yashikaaggarwal
Sir can you reveal official answer. Still not getting how the original price is 50.
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Sure, happy to help!
Official Answer:The reason that different original prices are possible is that we don't know the exact amount of the August discount. But, since we know the final price and the October discount, we can calculate the price after the August discount. Then, to find the lowest possible original price, we assume that the August discount was as small as possible (because the larger the discount required to reach any given price, the larger the original price must have been).
So, we'll start by calculating the price after the August discount but before the October discount. Let's call this price x dollars. Since this price dropped to $27 after a 10% discount, we can say that x– (10% of x) = 27. Because 10% is equivalent to 0.10, the equation becomes x– 0.10x = 27, or 0.90x = 27. Dividing both sides by 0.90, we have x = 30. So, the price was $30 after the August discount but before the October discount.
Now we assume the August discount was as small as possible, 40%. If y dollars is the original price, y– 0.40y = 30, or 0.60y = 30. Dividing both sides by 0.60, we have y = 50. The original price was $50, so (C) is correct.
Notice that we did not actually have to go through all the steps of setting up the equations each time we needed to work backwards to an original price. In general, we can get the answer more quickly by using the fact that Original Price = Discounted Price / (1-Discount). In fact, this is what we ended up with when we solved our equations.