Question
The profit on selling a book is 30%, and that on a pen is
20%. If profit on selling 2 books and 4 pens is Rs. 52, and on selling 3 books and 5 pens is Rs. 74, what is the cost price of a book?Solution
ATQ,
Let CP of a book = 100x
Let CP of a pen = 100y
SP of book = 130x, SP of pen = 120y
2(130x) + 4(120y) – 2(100x) – 4(100y) = 52
60x + 80y = 52 ……… (1)
3(130x) + 5(120y) – 3(100x) – 5(100y) = 74
90x + 100y = 74 ……… (2)
(1) × 5 → 300x + 400y = 260
(2) × 4 → 360x + 400y = 296
Subtract:
60x = 36 ⇒ x = 0.6
So, CP of book = 100x = Rs. 60
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