Question

Rubina has 12 fewer 20 -rupee notes than 10 -rupee notes. If she has Rs 330 in total, how many notes of each kind does she have?

Answer 1

$\blue{\bold{\underline{\underline{Answer:}}}}$

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$\green{\underline \bold{Given :}}$

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• Notes of Rs 20 are less than notes of Rs 10 by 12

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• Total amount by the notes is Rs 330

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$\red{\underline \bold{To \: Find:}}$

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• Number of Notes of each kind.

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$\large{\orange{\underline{\tt{Solution :-}}}}$

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Let no. of 20 Rs notes be 'y'

Let no. of 10 Rs notes be 'x'

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$\purple{\underline \bold{According \: to \: the \ question :}}$

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$\purple\longrightarrow$ $\sf y = x - 12$ -------(1)

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Also,

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$\sf \longmapsto 10x + 20y = 330$ --------(2)

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$\underline{\bold{\texttt{Putting value of y in (2)}}}$

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$\sf \longmapsto 10x + 20(x - 12) = 330$

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$\sf \longmapsto 10x + 20x - 240 = 330$

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$\sf \longmapsto 30x = 570$

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$\sf \longmapsto x = \dfrac { 570 } { 30 }$

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$\bf \dashrightarrow x = 19$

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$\underline{\bold{\texttt{Putting x = 19 in (1)}}}$

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$\sf \longmapsto 19 - 12 = y$

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$\bf \dashrightarrow y = 7$

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Hence number of 10 rupees note is 19 & number of 20 rupees note is 7

$\rule{200}5$