Question

By selling 90 ball pens for 180, a person loses 20%. How many ball pens should he sell for 96, so as
to have a gain of 20%?​

Answer 1

Answer:

S.P. of 90 ball pens = Rs.160,

Loss = 20%

∴ C.P. of 90 ball pens = Rs.

(100−20)

160×100

=Rs.

80

160×100

=Rs.200

∴ C.P. of 1 ball pen = Rs.

9

20

Suppose x ball pens are sold to earn a profit of 20 %

Then C.P. of x ball pens = Rs.

9

20

x

S.P. of x ball pens = Rs.96

∴Profit=Rs.(96−

9

20

x)

Given profit % = 20%

∴

9

20x

(96−

9

20

x)

×100=20⇒(96−

9

20x

)×5=

9

20x

⇒96−

9

20x

=

9

4x

⇒

9

24x

=96⇒x=

24

96×9

=36

∴ 36 ball pens should be sold for Rs.96 to earn a profit of 20%