A dealer bought 80 fountain pens of two qualities for a total sum of Rs.240. He paid Rs. 3.50 each for the better quality pen and Rs.2.25 each for the ordinary-quality pen. What is the number of better-quality pens bought by him?
Answers
Given :- A dealer bought 80 fountain pens of two qualities for a total sum of Rs.240. He paid Rs. 3.50 each for the better quality pen and Rs.2.25 each for the ordinary-quality pen. What is the number of better-quality pens bought by him ?
Solution :-
Let us assume that, the dealer bought x number of better-quality pens and y number of ordinary-quality pen .
so,
→ x + y = 80 ------ Eqn.(1)
→ 3.5x + 2.25y = 240 ------- Eqn.(2)
multiply Eqn.(1) by 2.25 and subtracting the result from Eqn.(2) we get,
→ (3.5x + 2.25y) - 2.25(x + y) = 240 - 2.25 * 80
→ 3.5x - 2.25x + 2.25y - 2.25y = 240 - 180
→ 1.25x = 60
→ x = 48 (Ans.)
Hence, the dealer bought 48 better-quality pens .
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