SOLUTION: Solve and verify your answer. A bookstore can purchase several calculators for a total cost of $300. If each calculator cost $1 less, the bookstore could purchase 10 additional

Algebra ->  Polynomials-and-rational-expressions -> SOLUTION: Solve and verify your answer. A bookstore can purchase several calculators for a total cost of $300. If each calculator cost $1 less, the bookstore could purchase 10 additional      Log On


   

Question 1130453: Solve and verify your answer.
A bookstore can purchase several calculators for a total cost of $300. If each calculator cost $1 less, the bookstore could purchase 10 additional calculators at the same total cost. How many calculators can be purchased at the regular price?
Answer by josmiceli(19441) About Me  (Show Source):
You can put this solution on YOUR website!
Let +n+= the original number of calculators
+300%2Fn+ = the original cost/calculator
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+%28+300%2Fn+-+1+%29%2A%28+n+%2B+10+%29+=+300+
+300+-+n+%2B+3000%2Fn+-+10+=+300+
+3000%2Fn+-+n+=+10++
+3000+-+n%5E2+=+10n+
+-n%5E2+-+10n+%2B+3000+=+0+
+%28+n+%2B+60+%29%2A%28+-n+%2B+50+%29+=+0+ ( by inspection )
+n+=+50+ ( can't use the negative solution )
50 calculators can be bought at original price
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check:
+%28+300%2F50+-+1+%29%2A%28+50+%2B+10+%29+=+300+
+%28+6+-+1+%29%2A60+=+300+
+5%2A60+=+300+
+300+=+300+
OK