CP = ₹ 180, gain = 20%
∴ SP = (120/100) x 180 = ₹ 216
Let the MP be ₹ P.
Then, 80% of P = 216

Correct Option: A

CP = ₹ 180, gain = 20%
∴ SP = (120/100) x 180 = ₹ 216
Let the MP be ₹ P.
Then, 80% of P = 216
∴ (80/100) x P = 216
⇒ P = (216 x 100)/80 = 270
Thus, MP is ₹ 270.

Let the CP be ₹ 100 and let MP be ₹ x above ₹ 100.
Then, MP = ₹ (100 + x) and discount =10%
∴ SP = [(90/100) x (100 + x)] = ₹ 177

Correct Option: B

Let the CP be ₹ 100 and let MP be ₹ x above ₹ 100.
Then, MP = ₹ (100 + x) and discount =10%
∴ SP = [(90/100) x (100 + x)] = ₹ 177
⇒ x = 30
So, cost should be labelled at 30% above CP.

Let the MP of a scooter = ₹ P
∴ CP of a scooter= ₹ 11P/13, Gain = 10%
SP = (110/100) x P= ₹ 11P/10
Gain = SP - CP = (11P/10 - 11P/13) = (143P - 110P)/130 = ₹ 33P/130

Correct Option: C

Let the MP of a scooter = ₹ P
∴ CP of a scooter= ₹ 11P/13, Gain = 10%
SP = (110/100) x P= ₹ 11P/10
Gain = SP - CP = (11P/10 - 11P/13) = (143P - 110P)/130 = ₹ 33P/130
Gain percentage = (33P/130) x (13/11P) x 100 % = 30%

CP. = (80% of 90% of ₹40000) + ₹(1200)

Correct Option: C

CP. = (80% of 90% of ₹40000) + ₹(1200)
= [(80/100) x (90/100) x 40000] + 1200
= (28800 + 1200)
= ₹30000
∴ CP = ₹30000
So, no gain no loss in the transaction.

Gain percentage = [Error/(True value - Error)] x 100 %
= [(100/(1000 - 100)] x 100 %

Correct Option: A

Gain percentage = [Error/(True value - Error)] x 100 %
= [(100/(1000 - 100)] x 100 %
= (100/900) x 100 %
= 11¹/₉%