Question 522110
A man sold half an egg more than half his eggs.
e - (.5e+.5)
e - .5e - .5
.5e - .5 left
:
 He then sold half an egg more than half his remaining eggs.
(.5e-.5) - .5(.5e-.5) - .5
.5e - .5 - .25e + .25 - .5
.25e - .75 left
:
 He did the same a third time, and then he had 7 eggs left.
(.25e-.75) - .5(.25e-.75) - .5 = 7
.25e - .75 - .125e + .375 - .5 = 7
.125e - .875 = 7
.125e = 7 + .875
.125e = 7.875 
e = {{{7.875/.125}}}
e = 63 eggs to start with
:
:
Check this by substituting at each stage of the problem
1st: .5(63) -.5 = 30 eggs
2nd: .25(63) -.75 = 15 eggs
last: .125(63)-.875 = 7 eggs