Question

By selling 90 ball pens for Rs 160 a person loses 20%. How many ball pens should be sold for Rs 96 so as to have profit of 20%?

Answer 1

You need to sell 36 ball pens to have 20% profit .

Answer 2

S.P of 90 ball pens
=
R
s
.
160
∴
S.P of 1 ball pen
=
R
s
.
160
90
=
R
s
.
16
9
Loss
=
20
%
∴
C.P of one pen
=
S
.
P
×
100
100
−
l
o
s
s
%
=
16
×
100
9
(
100
−
20
)
=
R
s
.

16
×
100
9
×
80
=
R
s
.

20
9
In second case,
Gain
=
20
%
S.P of one pen
=
C
.
P
×
(
100
+
g
a
i
n
%
)
100
=
20
9
×
(
100
+
20
)
100
=
R
s
.

20
9
×
120
100
=
R
s
.

8
3
In
R
s
.

8
3
, ball pens will be sold = 1
∴
In Rs. 96, ball pens will be sold
=
1
×
3
8
×
96
=
36