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$2 p+ m= 135$ whereas $p + 2m = 120$ And $p+ m+ a = 100$ Find $a$.

Basic algebra but can't get sensible answer (:

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    Hint: look at your first two equalities. What do you get if you add them?2012-09-15

1 Answers 1

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After adding equality $1$ and equality $2$, we get the following:$3m + 3p = 255$We may divide both sides by $3$ to get,$m + p = 85 $Since we already have $m + p = 85 $, we see that $m + p + a$ can be written as $85 + a$(substituting $m + p$ with $85$).

We are left with the equation:$ 85 + a = 100$Clearly, $a = 15$

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    Thank you very much! This was comparatively an _easy_ problem, thus making me have a go at it.2012-09-15