Question

Find the sum of all the natural number between 50 and 500 which are divisible by 7

Answer 1

Answer:

it is your answer.i hope this helps you.

Answer 2

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

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

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• Sum of all the natural numbers between 50 & 500 which are divisible by 7.

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

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$\underline{\bold{\texttt{Let us write an AP for it}}}$

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$\sf \longmapsto 56, 63, 70................497$

Let 497 be 'n' [n = number of integer]

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$\underline{\bold{\texttt{We know that}}}$

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$\sf \implies a_n = a + (n - 1)d$

[$\sf a_n = 497 , a = 56 , d = 7$ ]

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$\underline{\bold{\texttt{Putting these value we get :}}}$

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$\sf \implies 497 = 56 + (n - 1)7$

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$\sf \implies 497 - 56 = (n - 1)7$

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$\sf \implies 441 = (n - 1)7$

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$\sf \implies n - 1 = { 441 } { 7 }$

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$\sf \implies n - 1 = 63$

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$\sf \implies n = 64$

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$\underline{\bold{\texttt{We know that}}}$

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$\sf S_n = \frac { n } { 2 } [ 2a + (n - 1)d ]$

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$\sf S_n = \frac { 64 } { 2 } [ 2(56) + (63)(7)]$

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$\sf S_n = 32 [ 112 + 441 ]$

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$\sf S_n = 32 [ 553 ]$

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$\sf S_n = 17696$

Hence the sum of natural number between 50 & 500 which is divisible by 7 is 17696