rrect answer.The cost of a certain number of pens is ₹72. If the cost of each pen is decreased by then 8 more pens can be purchased for the same amount. How many pens can be purey for the same amount if the cost of each pen is increased by ₹1.50 ?
Q. rrect answer.The cost of a certain number of pens is ₹72. If the cost of each pen is decreased by then 8 more pens can be purchased for the same amount. How many pens can be purey for the same amount if the cost of each pen is increased by ₹1.50 ?
Define x as original cost: Let x be the original cost of each pen. Then the number of pens that can be bought for ₹72 is x72.
Calculate new cost: If the cost of each pen is decreased by ₹1, then the new cost of each pen is x−1. So, 8 more pens can be bought, which means the new number of pens that can be bought for ₹72 is 72/(x−1).
Formulate equation: According to the problem, the number of pens bought for ₹72 at the original price is 8 less than the number of pens bought at the reduced price. So, we have the equation x72+8=x−172.
Clear denominators: Multiply both sides of the equation by x(x−1) to clear the denominators: x(x−1)(x72+8)=x(x−1)(x−172).
Simplify equation: Simplify the equation: 72(x−1)+8x(x−1)=72x.
Combine like terms: Distribute and combine like terms: 72x−72+8x2−8x=72x.
Subtract 72x: Subtract 72x from both sides to get: 8x2−8x−72=0.
Divide by 8: Divide the entire equation by 8 to simplify: x2−x−9=0.
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