Question

Q:If nC3=56, then value of n is​

Answer 1

Answer:

Answer is 8.

It is correct answer.

Answer 2

SOLUTION

GIVEN

$\displaystyle \sf{ {}^{n}C_3 = 56 }$

TO DETERMINE

The value of n

EVALUATION

Here it is given that

$\displaystyle \sf{ {}^{n}C_3 = 56 }$

Now we have

$\displaystyle \sf{ {}^{n}C_3 = 8 \times 7 }$

$\displaystyle \sf{ \implies {}^{n}C_3 = \frac{8 \times 7 \times 6}{6} }$

$\displaystyle \sf{ \implies {}^{n}C_3 = \frac{8 \times 7 \times 6 \times 5!}{3! \times 5!} }$

$\displaystyle \sf{ \implies {}^{n}C_3 = \frac{8 !}{3! \times 5!} }$

$\displaystyle \sf{ \implies {}^{n}C_3 = {}^{8}C_3 }$

Comparing both sides we get n = 8

FINAL ANSWER

Hence the required value of n = 8

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