a man buys a few number of books at rs 72 each and a few number of pens at rs 25 each. if he buys 11 articles and pay rs 510 altogether , find the number of each articles bought by him.
Answers
Given,
Cost of each book = Rs 72
Cost of each pen = Rs 25
Total no. of articles bought = 11
Total amount paid = 510
To find,
Number of articles (books and pens) bought = ?
Solution,
Let the number of pens be x and number of books be y
Total number of articles = 11
∵ x + y = 11
y = 11 - x (i)
Therefore,
cost of pens bought = 25x
cost of books bought = 72 (11-x)
Total amount paid is 510.
25x + 72y = 510 (ii)
25x + 72 (11-x) = 510
25x + 792 - 72x = 510
792 - 510 = 47x
282 = 47x
6 = x (iii)
Using (ii) in (i)
y = 11 - 6
y = 5 (iv)
Replacing (iii) and (iv) in equation (ii)
25 × 6 + 72 × 5 = 510
150 + 360 = 510
510 = 510
LHS = RHS
Therefore the number of pens bought is 6 and number of books bought is 5 for Rs 510.