Math, asked by vidhanmaheshwap5kv8u, 1 year ago

nC7=nC4 find value of n

Answers

Answered by SunilChoudhary1
13
here is your answer

n= 7+4

n=11...........
Answered by gratefuljarette
15

The value of n is 11

Given:  

_{7}^{n} C=_{4}^{n} C

To find:

The value of n

Solution:

The question  _{7}^{n} C=_{4}^{n} C is according to the formula of \stackrel{n}{r} C=\frac{n !}{r !}(n-r) !, so write the values in the formula, we get\left(\stackrel{n}{7} C=\frac{n !}{7 !(n-7) !}\right)= \left(\stackrel{n}{4} C=\frac{n !}{4 !(n-4) !}\right), now putting the value and find the combination of  

\frac{n !}{7 !(n-7) !}=\frac{n !}{4 !(n-4) !}

Dividing both sides by n! we get the following equation below

\frac{1}{7 !(n-7) !}=\frac{1}{4 !(n-4) !}, taking cross multiplication we get

4 !(n-4) !=7 !(n-7) !, we pull the division of  7! And 4! On one side of the equal we get

\frac{(n-4) !}{(n-7) !}=\frac{7 !}{4 !} 210 \text { we get }(n-4)(n-5)(n-6)=210

solving the n equation we get n = 11.

Hence, the value of n is 11

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