two women were selling wrist bands in the close-by shops, one at three for an euro and other at two for an euro. one day both of them were obliged to return home when each had sold thirty bands unsold. They put together the two lots of marbles and handing them over to a friend and asked her to sell them at five for two euros.According to their calculation, after all, three for an euro and and two for an euro was exactly the same as five for two euros. Now they were expecting 25 euros as they would have normally got.Much to their surprise they got 24 euros for the whole lot. Now where did the one euro go? Can you explain the mystery?
30 bands at the cost of 3 bands per euro were sold with 20 bands at the cost of 2 bands per euro, Thus they received 20 euros for this, while the other 10 bands were sold at 5 bands per two euro, thus received 4 euros additional.
Here there expectation were wrong due to the fact that 10 bands which were supposed to be sold originally at 4 bands per two euros, were instead sold at 5 bands per two euros.
while mixing articles, the cost of articles are taken as the average price of both articles.
3 bands = 1 euro, 1 band = 1/3 euro
2 bands= 1 euro, 1 band = 1/2 euro,
when we mix them , the price of 1 band = avg (1/3 + 1/2) = 5/12, and 5/12 * 60 bands = 25
when 5 bands = 2 euros, price of 1 band = 2/5, 2/5*60 bands= 24 euros
we can see for each band sold, we lost 5/12 – 2/5 = 1/60, when 60 bands sold, 1 euro will be lost.