Question

6. Rajeshwar bought 16 dozen ballpoint-pens and sold them one by one. Due to a
calculation mistake in fixing the selling price, he lost an amount equal to the S.P. of 4
dozen pens. Find his loss %. Find the S.P. of one dozen pens, if he purchased these
16 dozen pens for 240.​

Answer 1

Loss = C.P. of 16 dozen pens - S.P. of 16 dozen pens

=> S.P. of 4 dozen pens = C.P. of 16 dozen pens - S.P. of 16 dozen pens

=> C.P. of 16 dozen pens = S.P. of 20 dozen pens

=> C.P. of 16 pens = S.P. of 20 pens

=> C.P. of 4 pens = S.P. of 5 pens

=> S.P. of 1 pen = 4/5 × C.P. of 1 pen ...(1)

Let C.P. of one pen = Rs.1

Then S.P. of one pen = Rs.4/5 [from (1)]

loss percentage = (C.P. of one pen - S.P. of one pen)/100

C.P. of one pen=(1−4/5)/100=20%

Suppose he purchased 16 dozen pens for Rs 240

=> C.P. of 1 dozen = 240/16=Rs.15

Since the loss is 20%, S.P. of 1 dozen = 15×80/100= Rs.12

Answer 2

Answer:

240 ÷ 16 = 15 + 4 = 19

If 16 dozen pens = 240 Rupees

so , 1 dozen pens = 240 ÷ 16 = 15

According to question loss = 4

In percentage = 4/ 16 × 100

2/4×100

1/2×100 = 50 %