Tree leaves.  🙂

they suffered  the loss of a rupee..

In second case when they sold the oranges together then cost earned for each orange was Rs. 0.4(24/60)

whereas in  first  case
lets suppose Lady 1:- who sells orange at 3  for re 1.
Lady 2:- who sells orange at 2  for re 1.
if we jointly frame the sets  then lady 1  can make 10 sets whereas number will be 15 for lady 2.
for first 20  sets sold ( 10 from lady 1 and 10 from lady 2) joint cost  charged for each orange will be 0.4.  till now matter lies as no profit for them.
now remaining  5 sets are sold by lady 2 at 1 re per set  which means 0.5 paise per orange. and she charges this rate for 5 set == 10 oranges … Here the difference in pice arise … each Orange is sold at 0.10 higher price.. therefore for 10 oranges profit sums upto 0.10*10=1 Re.    Which makes the difference