what’s the logic for the answer. | Mathematics | Page 1

fallen parrot Jun 23, 2024, 1:25 PM

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If a : b = 3:4, the value of (2a + 3b) : (3a + 4b) is?
This is a problem form Ratio and Proportion.
What I can’t grasp is how replacing the variable with the ratio results in a correct answer…

nimble islandBOT Jun 23, 2024, 1:25 PM

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hard agate Jun 23, 2024, 1:58 PM

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well you can consider this

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a:b = x:y can be written in terms of fractions that is a/b = x/y

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and hence ay = bx

young whale Jun 23, 2024, 2:55 PM

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since a and b are already given, substitute them

a:b = 3:4
so...
a=3, b=4

substitute the values, do the necessary operations then you'll have your ratio

alpine zealot Jun 23, 2024, 2:58 PM

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say a = 3x

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and b = 4x

young whale Jun 23, 2024, 2:58 PM

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no

alpine zealot Jun 23, 2024, 2:58 PM

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subsitute these in into the varables

young whale Jun 23, 2024, 2:59 PM

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remove x

alpine zealot Jun 23, 2024, 2:59 PM

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how so

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no

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u didnt do general case

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wut if a=6 and b=8

young whale Jun 23, 2024, 2:59 PM

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really? x should be included?

alpine zealot Jun 23, 2024, 2:59 PM

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well

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for this question, no

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like to solve it

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but if you want to write like a formal proof

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you should generalize your stuff

young whale Jun 23, 2024, 3:00 PM

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ohh

fallen parrot Jun 23, 2024, 5:26 PM

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Ooh got it..

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.close

#what’s the logic for the answer.