SOLUTION: The price of sugar decreased by 20% and this decrease in price enables a man to purchase 1kg more of sugar for Rs. 90/-. find the present as well as the previous price of sugar per

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Question 887664: The price of sugar decreased by 20% and this decrease in price enables a man to purchase 1kg more of sugar for Rs. 90/-. find the present as well as the previous price of sugar per kg.
Answer by josgarithmetic(39615) About Me  (Show Source):
You can put this solution on YOUR website!
Let p = the original price
Let q = the original quantity purchased
ASSUME that the original purchase for for Rs. 90 AND this is the same amount of Rs. for the purchase at the reduced price (which was actually given).

Before the discount, p%2Aq=90

After new discount price, %280.8%29p%28q%2B1%29=90, 80% of original price is same as 20% discount price.

At discount, simplification... 0.8pq%2B0.8p=90
pq%2Bp=90%2F0.8
pq%2Bp=225%2F2
Substitute using "before" equation,
90%2Bp=225%2F2
p=225%2F2-90
highlight%28p=22.5%29 Rs. The original or previous price.

You want to find 80% of 22.5 for knowing the discount price.