A shopkeeper earns a profit of rupee 1 by selling one pen and incurs a loss of 40 paise per pencil while selling pencils of his old stock.
(1) In a particular month he earns neither profit nor loss. If he sold 70 pens, how many pencils did he sell? (a) 125 pencils (b) 175 pencils
(2) In a next month he incurs a loss of rupee 5. In this period, he sold 45 pens. How many pencils did he sell in this period.
Answers
Step-by-step explanation :
Let us consider that selling price of each pen = ₹1
And selling price of each pencil = ₹0.4
Q.1 Earning of one month = neither profit nor loss
Therefore, let us consider the pencils as x
total price of 70 pens = total price of x pencils
S.P of 70 pens = ₹1 × 70
= ₹70 ............... (i)
S.P of x pencils = x × ₹0.4
= ₹0.4 x ............... (ii)
Substituting value of equation (i) in (ii)
₹70 = ₹0.4 x
x = ₹70/0.4
x = 70 × 10/4
x = 175 pencils
Option - (b) 175 pencils
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Q.2 Earning of second month = loss of ₹5
Total price of 45 pens = ₹1 × 45
= ₹45 ...............(i)
Total price of x pencils = ₹0.4 × x
= ₹0.4 x ..............(ii)
As loss of ₹5, total amount ⇒ ₹45 + ₹5 = ₹50
Again substituting value of equation (i) in (ii)
₹50 = ₹0.4 x
₹50/₹0.4 = x
x = 50 × 10/4
x = 125 pencils