SOLUTION: Three boys are talking about how many sweets they each have. A: B has the most! B: If C gave me one sweet, I'd have twice as many as A does. C: It'd be better if B gave me two

Algebra ->  Customizable Word Problem Solvers  -> Coins -> SOLUTION: Three boys are talking about how many sweets they each have. A: B has the most! B: If C gave me one sweet, I'd have twice as many as A does. C: It'd be better if B gave me two      Log On

Ad: Over 600 Algebra Word Problems at edhelper.com


   



Question 846445: Three boys are talking about how many sweets they each have.
A: B has the most!
B: If C gave me one sweet, I'd have twice as many as A does.
C: It'd be better if B gave me two sweets. Then we'd all have the same amount!
How many sweets are there in total?
I know the answer but the algebra is giving me trouble.

Answer by KMST(5347) About Me  (Show Source):
You can put this solution on YOUR website!
A= number of sweets A has.
B= number of sweets B has.
C= number of sweets C has.
We could even define N=A%2BB%2BC .

The fact that C says
"It'd be better if B gave me two sweets. Then we'd all have the same amount!"
means B-2=C%2B2=A .
That is 3 equations, but not independent, so it is worth 2 equations.

The fact that B says
"If C gave me one sweet, I'd have twice as many as A does."
means that B%2B1=2A .
With that last equation, we have 3 independent equations, and that's enough to solve.
system%28A=B-2%2CA=C%2B2%2CB%2B1=2A%29
We could even add N=A%2BB%2BC and say we have a system of 4 linear equations, but why complicate when you can make it simpler.

Since two of the equations in system%28A=B-2%2CA=C%2B2%2CB%2B1=2A%29 have only A and B, I can solve for A and B with just two equations:
system%28A=B-2%2CB%2B1=2A%29 --> system%28A=B-2%2CB%2B1=2%28B-2%29%29 --> system%28A=B-2%2CB%2B1=2B-4%29%29 --> system%28A=B-2%2CB%2B5=2B%29%29 --> system%28A=B-2%2C5=B%29%29 --> system%28A=5-2%2Chighlight%28B=5%29%29%29 --> highlight%28system%28A=3%2CB=5%29%29%29

Now I can use the results above and the equation I have not used to find C.
system%28A=3%2CA=C%2B2%29 --> 3=C%2B2 --> 3-2=C --> highlight%28C=1%29

Now, I can find the total
A%2BB%2BC=3%2B5%2B1 --> A%2BB%2BC=highlight%289%29