A person loses Rs. 20 by selling some bananas at the rate of Rs. 3 per banana and gains Rs.30, if he sells them at Rs. 3.25 per banana. The number of bananas sold by him?

Price after 10% discount = 10000 - 10 % of 10000 = 10000 - 0.1 x 10000 = 9000
Price after another 20% discount = 9000 - 20 % of 9000 = 7200
Price after 10% of transportation charges = 7200 + 7200 x 0.1 = 7920
Price after 10% of profit = 7920 + 7920 x 0.1 = 8712
? Selling price = 8712

CP = 405 / 0.9 = 450
New SP = Rs. 465
Profit (%) = [465-450 / 450] X 100 = 3.33%

Here, 6 apples are gained over 18 apple.
? Gain percent = (6/18) x 100 %
= 33¹/₃%

Profit on one calculator
= 250[1- (100/114)] = ? 30.70

? Total amount of the profit
= 19 x 7 x 30.70
= ? 4083.10

Let CP = N
According to the question
(106N/100) - (104N/100) = 3
? 2N/100 = 3
? N = 300/2
= ? 150

Profit (%) = goods lefts / goods sold X 100 = ( 50 / 450 ) X 100 = 11¹/₉ %

Alternatively : Suppose CP of 1g is Rs.1 then he sells goods worth Rs.450 only and charges Rs.500. So the profit is Rs.50 over the sale price of Rs. 450.

The best way is to go through option. Consider option (a)
Total profit = 15000 x ( 2 / 3 ) x 5 %
= 15000 x ( 2 / 3 ) x ( 5 / 100) = 500

Total loss = 15000 x ( 1 / 3 ) x 2 %
= 5000 x ( 1 / 3 ) x ( 2 / 100) = 100

Net gain = ( 500 - 100 ) = Rs. 400
Hence: option (a) is correct.

Alternatively : [( 1.05 X 2x/3 + 0.98 x/3) - x] = 400
? x=15000

Let the cost price of one gram be Rs. 1, then the mark up price be Rs. 1.2 per g.

Now he sells 1000 g which seems to be 1250 g so he charges to a customer 1250 X 1.2 = Rs. 1500 for 1000 g (or Rs. 1000)

Thus his profit % 1500 -1000 / 1000 X 100 = 50 %

Cost price (CP) = 10 / 12 ,
Selling price (SP) = 12 / 10


Profit (%) = [ (SP - CP) / CP ] x 100
? Profit (%) = [( 12 / 10 - 10 / 12 ) / (10 / 12) ] X 100 = 44 %

Let's assume the cost price be (CP) = x
So selling price (SP) = 112.5x
Price marked on good ( MP ) = 300

According to question MP - 25% = SP
? x = 200, hence the cost price be Rs. 200.