If $^{15} C_{3 r} =^{15} C_{r + 3}$ , then find the value of $r$ :

3

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2

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0

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1

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Solution

The correct option is A $3$
$^{15} C_{3 r} =^{15} C_{r + 3}$
We Know
$^{15} C_{3 r} =^{15} C_{r + 3}^{n} C_{r} =^{n} C_{n - r} n = r + (n - r) = 3 r + r + 3 = 4 r + 3 \Rightarrow 4 r + 3 = 15 \Rightarrow 4 r = 12 \Rightarrow r = 3$

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Similar questions

^{15} C_{3 r} =^{15} C_{r + 3}

Find $r$ if $^{15} C_{3 r} =^{15} C_{r + 3}$

^{15} C_{3 r} =^{15} C_{r + 3}

^{15} C_{3 r} :^{15} C_{r + 1} = 11 : 3

r

^{15} C_{3 r} :^{15} C_{r + 1} = 11 : 3

r

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