Egg Problem

One lady who made a living by selling eggs had 90 eggs which she wanted to sell, so she sent her three daughters to the market, giving 10 eggs to her eldest and cleverest daughter, 30 to the second and 50 to the third.

'You'd better agree among yourselves.' she told to them ,'about the price you're going to ask for the eggs, and keep to it. Stick to the price you decide upon.But I hope that in-spite your agreement, the eldest being the cleverest, will receive as much as for her 10 eggs as the second will receive for her thirty and will teach the second to sell her thirty eggs for as much as the younger will sell her thirty. In other words each of you is to be bring home the same amount and the total for 90 eggs is to be 90 rupees.'

I typed it myself so if you feel any information missing plzz reply.and explain how they would sell the eggs...