Question

Reena sold two articles @ 840 each on one she gain 20% and on the other she losses 20% how much does she profit or lose in the whole transaction

Answer 1

SP = Rs. 840

if gain = 20%
gain% = (SP-CP)/CP * 100
⇒ 20= (840-CP)/CP * 100
⇒ 20/100 = (840-CP)/CP
⇒ 0.20CP = 840 - CP
⇒ 0.20CP + CP = 840
⇒ CP = 840/1.2 = Rs. 700

if loss = 20%
loss% = (CP-SP)/CP * 100
⇒ 20 = (CP-840)/CP * 100
⇒ 20/100 = (CP-840)/CP
⇒ 0.20CP = CP - 840
⇒ CP - 0.20CP = 840
⇒ CP = 840/0.8 = Rs. 1050

Total CP = 700+1050 = 1750
Total SP = 840+840 = 1680

loss = 1750- 1680= Rs. 70
loss% = loss/CP * 100 = 70/1750 * 100=4%.

Answer 2

SP=Rs.840

gain=20%

gain%=

CP

(SP−CP)

×100

20=

CP

(840−CP)

×100

Solving the above equation, we get,

0.20CP+CP=840

CP=

1.2

840

=Rs.700

loss=20%

loss% =

CP

(CP−SP)

×100

20=

CP

(CP−840)

×100

Solving the above equation, we get,

CP−0.20CP=840

CP=

0.8

840

=Rs.1050

Total−CP=700+1050=1750

Total−SP=840+840=1680

loss=1750−1680=Rs.70

loss%=

CP

loss

×100=

1750

70

×100=4%