SOLUTION: Derek brought raisins for lunch and shared them with some of his classmates. He gave half of his raisins to Mollythen ate one himself. After that he gave half of the remainging to

Question 163461: Derek brought raisins for lunch and shared them with some of his classmates. He gave half of his raisins to Mollythen ate one himself. After that he gave half of the remainging to Tricia and ate another on himself. Finally, he gave half of the remainging raisins to Clark, and had 7 raising left. Hoaw amny raisins did Derek start with?

Answer by ankor@dixie-net.com(22740) (Show Source): You can put this solution on YOUR website!
Derek brought raisins for lunch and shared them with some of his classmates.
He gave half of his raisins to Molly then ate one himself. After that he gave
half of the remaining to Tricia and ate another one himself. Finally, he gave
half of the remaining raisins to Clark, and had 7 raising left.
How many raisins did Derek start with?
;
Let x = no. of raisins to start with
:
x - .5x - 1; Molly
(.5x-1); remaining
:
(.5x-1) - .5(.5x-1) - 1; Tricia
.5x - 1 - .25x + .5 - 1
.5x - .25x +.5 - 1 - 1
.25x - 1.5; remaining
:
(.25x-1.5) - .5(.25-1.5) - 1; Clark
.25x - 1.5 - .125 + .75 - 1
.25x - .125x - 1.5 + .75 - 1
.125x - 1.75 = 7; remaining
.125x = 7 + 1.75
.125x = 8.75
x =
x = 70 raisins to start with
:
:
Let's see if that flies:
70 - 35 - 1 = 34
34 - 17 - 1 = 16
16 - 8 - 1 = 7, hooray! it does

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