Lets assume that two woman’s as A&B

It has given A has 30 marbles and B has 30 marbles

If they given to friend to sell 5 marbles for 2 paise than

60=12*5 i..e  12*2 = 24 paise

But if they sell separately

A would have made

1)      A sells 3 marbles for 1 paise so

30=10*3 i..e  10*1=10 paise

B would have made

1) B sells 2 marbles for 1 paise so

    30=15*2 i.e 15*1=15 paise

combing A&B gives you 10+15=25

the above is only explanation

                   due to combination it will give 1 paise difference thats all

Each women had 30 marbles.

First women : 3 marbles per paise, then she would have sold 10 sets of marbles(cheap marble)

Second women: 2 marbles per paise, then she would have sold 15 sets of marbles(costlier marble)

When the two types of marbles were combined, we got 60 marbles, 5 marbles per 2 paise. No of sets would be 12 sets.

As you can see, after selling 10 sets the cheapest marbles will be over. the remaining 2 sets i.e 10 marbles will be of costlier kind.

Till the 10 sets the combination is 3 cheap + 2 costlier

Now after selling 10 sets, 2 costlier + 2 coslier + 1 coslier makes a set

the cost of this combination should be 1 paise + 1 paise + 1/2 paise =  2 1/2 paise.

But the women sold this combination also for 2 paise, that is why we got 1 paise difference

The problem is so simple......:-)

Total number of the unsoled marbels are.. 60

cost is 5 marbles for 2 paise..

there will be 12 sets...

12*2 is 24 paise is the final income...

But there will be 12(3 & 2) set of each marbles=12 set(5) of combined marbels.

cost of total of 36 cheaper marbel and 24 costlier marbels is 24

But there are only 30 cheaper and 30 costlier.

After 10 set of 5 marbels only costlier marbels are left..

Point is that two women got confused.. thinking this way

each of them were selling at 3 / P and 2 / P and each got equal numbers in their hand i.e 30+30.. so they averaged the sales bye (3+2)/2.. i.e by selling 5 / P they will get same earnings as they original would have got if sold idividually. Their assumption is wrong.. to get same amount the would hv done as below

A's return 30/3 = 10P

B's expected return 30/2 = 15P

A+B's expected return = 25P

Hence they would have fixed the combined price as 60/25 per P i.e 12/5 (i.e 12 per 5P which is 2.4 for every P. However with the averaging confusion they sold at 5/2P which is 2.5 for every P.

Hence while selling they received only 60/2.5 = 24P insted of their expectation of 60/2.4 = 25P

Each women had 30 marbles.

First women : 3 marbles per paise, then she would have sold 10 sets of marbles(cheap marble)

Second women: 2 marbles per paise, then she would have sold 15 sets of marbles(costlier marble)

When the two types of marbles were combined, we got 60 marbles, 5 marbles per 2 paise. No of sets would be 12 sets.

As you can see, after selling 10 sets the cheapest marbles will be over. the remaining 2 sets i.e 10 marbles will be of costlier kind.

Till the 10 sets the combination is 3 cheap + 2 costlier

Now after selling 10 sets, 2 costlier + 2 coslier + 1 coslier makes a set

the cost of this combination should be 1 paise + 1 paise + 1/2 paise =  2 1/2 paise.

But the women sold this combination also for 2 paise, that is why we got 1 paise difference

one women sells 3 marbles for 1 paise

so for 1 marble it costs 1/3 paise

for 30 marbles 1/3*30=10 paisse
 
second women sells 2 marbles for 1 paise

so for 1 marble 1/2 paise

for 30 marbles 1/2*30=15 paise

totally 10 +15 is 25 paise

but  now they are selling at 5 marbles for 2 paise

so for 1 marble 2/5 paise

for 30+30=60 marble 2/5*60=24 paise