Question

A shopkeeper gains ₹1 on selling a pen and looses 50 paise on selling a pencil. Represent the gain and loss in terms of integers.

(i) There is a loss of ₹5 in a month. If he had sold 45 pens then find the number of pencils, sold by him in a month.

(ii) There is no profit and no loss in the second month. If he sold 70 pens and the number of pencils sold.

Answer 1

Integer form, of gain of ₹1 = + 100 and integer form of loss of 50 paise = – 50

(i) Gain on selling 45 pens = ₹45

= 45 x 100 = 4500 Paise

Let x pencils are sold

∴ Loss on selling x pencil = – x × 50

= – 50x Paise

According to question,

Loss on(45 Pen + x Pencil) = -₹5

= – 500 Paise

⇒ 4500 Paise – 50x Paise = -500 Paise

⇒ -50x = -500 – 4500

⇒ x = -5000/-50 = 100

∴ Number of pencils sold = 100

(ii) Gain on selling 70 Pen = ₹70

= 70 x 100 = 7000 Paise

∵ There is not loss or gain

∴ Total loss = Total gain

∴ Loss on selling x pencils = 7000 Paise

Loss on 1 pencil = 50 Paise

∴ Loss on x pencils = 50x Paise

⇒ 50x = 7000

⇒ x = 7000/50

⇒ x = 140

∴Number of pencils sold = 140