math..word problem
posted by M.A. .
Mary had some M&M candy. She ate one, then gave half of the remaining candy to Bill. She ate another candy, then gave 1/3 of the remaining to Edie, leaving 6. How many did she give away to Bill and Edie?

40???

If there are 6 left after Mary has given a third to Edie then there must have been 9 to start with and she gave 3 to Edie.
Before she ate one there must have been 10 sweets.
So after giving half to Bill she has 10 left there must have been 20 to start with and she gave 10 to Bill.
Thus she gave 3+10 = 13 to Bill and Edie.
Just check my maths. No idea how you got to 40. 
oops, i misread the problem

Don't forget the one she ate before she gave 1/2 to Bill. I got that she started with 21.

"Don't forget the one she ate before she gave 1/2 to Bill. I got that she started with 21" But that is not the question, the question asks "how many she gave to Bill and Edie?", NOT "how many did she start with?"

Thank you. I can follow the solution quite easily as explained, but I could never have come up with the solution from scratch other than just starting with numbers and trial and error. So how do you begin such a problem?