Author Topic: Maths help  (Read 808 times)

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Offline MetalJunkie

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Maths help
« on: September 25, 2017, 09:09:23 PM »
I'm helping a friend with homework and it's been ages since I've done this stuff. I can figure it out, but I'm guessing there's a formula that will do it faster than my "guess and check"

This is the problem:


From that, I tried to reduce it to actual equations to make it simpler for myself to figure it out. I came up with

A + B + C = 50

A + 6 = B

A + 8 = C

I just kept plugging numbers into the variables until I got the right answers. Surely there's an easier way than throwing a random number into those variables, like an actual formula or process for this?
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Offline jingle.boy

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Re: Maths help
« Reply #1 on: September 25, 2017, 09:16:27 PM »
Given the above substitute what B equals, and what C equals into the original formula.

A + (A + 6) + (A + 8) = 50

3A = 36

A = 12

thus...

B = 18
C = 20

You did all the hard work by translating the word problem into formulas!
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Offline jasc15

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Re: Maths help
« Reply #2 on: September 29, 2017, 03:10:53 PM »
Surely there's an easier way than throwing a random number into those variables, like an actual formula or process for this?
Write the equations exactly as they are written in the problem:

"middle piece is 6 inches shorter than shortest piece"

          M = S + 6     or     M - 6 = S

"Shortest piece is 8 inches shorter than the longest piece"

          S = L - 8     or     L = S + 8

Then make everything in terms of one of the 3 pieces by substituting the above equations into this:

           S + M + L = 50