A vendor purchased bananas at Rs.40 per dozen and sold them at 10 for Rs. 36. Find his gain or loss per cent.
SP of 1 Banana = 36/10
= Rs.3.6
SP of 1 Dozen Banana = 3.6 × 12
= Rs.43.20
CP of 1 Dozen Banana = Rs.40
Gain = SP – CP
= 43.20 – 40
=3.2
=
= 8%