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Math word problem
Quote:
Three Friends sit down to eat 14 slices of Pizza.If two of the Friends eat the same number of slices ,and the third eats two more slices than each of the other two,how many slices are eaten by the third friend?“Three Friends sit down to eat 14 slices of Pizza.”
f1 + f2 + f3 = 14“If two of the Friends eat the same number of slices”
f1 = f2“third eats two more slices than each of the other two”
f3 = f2 + 2
f3 = f1 + 2“how many slices are eaten by the third friend?”
f3 = ?Look at the information you have. Do you have enough information? Do you the number of equations equal the number of variables?
1) f1 + f2 + f3 = 14
2) f1 = f2
3) f3 = f2 + 2
4) f3 = f1 + 2
Well, you have 3 unknowns and 4 equations. More equations than unknowns means you can answer this question! So now let’s do it!since f1 = f2, you can rewrite #1:
f2 + f2 + f3 = 14Since we want to solve for f3, we want to leave all the f3’s in there, but express f2 with f3 inside of it. Look for an equation that has both f2 and f3 in it
Aha! f3 = f2+2
express f2 as a function of f3 so that you can plug it in later
f2 = f3 – 2Now plug it in to: f2 + f2 + f3 = 14, or 2f2 + f3 = 14
2 (f3-2) + f3 = 14
2f3 – 4 + f3 = 14
3f3 = 18f3 = 6
Voila! The third guy ate six slices!!
And of course the other two guys must have eaten 2 less, so that would be 6-2 = 4 slices
4 responses to “Math word problem”
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Megan
how did you come about with this forumula
f3 = f1 + f2
it is not possible with the following statement to come with the above formula.
“third eats two more slices than each of the other two”
please explain
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Ozzie
It’s too long, you won’t have that much time during the test so it’s easier if the thinking’s like this:
f1 = f2 and f3 = f1 + 2
so
f1 + f2 + f3 = 14 is equal to f1+f1+f1+2=14
which can be simplified to 3f1=12; f1=4
Since f3 = f1+2 then f3 = 4+2 = 6 -
Marc
The fastest way I think of it is this:
Friends 1 and 2 are the same, friend 3 has 2 more.
Therefore, f3 – 2 = f1 = f2
Therefore, 14 – 2 = 12/3 = 4.
Pretty much like ozzie. But an answer should be reached within a few seconds if done in your head
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Marc
Oh and so f3 = 4 + 2 = 6.
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