Search any question & find its solution
Question:
Answered & Verified by Expert
If ${ }^n C_3=220$, then $n=$ ?
Options:
Solution:
1941 Upvotes
Verified Answer
The correct answer is:
12
We have, ${ }^n C_3=220$
$$
\begin{array}{ll}
\Rightarrow & \frac{n(n-1)(n-2)}{6}=220 \\
\Rightarrow & n(n-1)(n-2)=1320 \\
\Rightarrow & n=12 \quad[\because 12 \times 11 \times 10=1320]
\end{array}
$$
$$
\begin{array}{ll}
\Rightarrow & \frac{n(n-1)(n-2)}{6}=220 \\
\Rightarrow & n(n-1)(n-2)=1320 \\
\Rightarrow & n=12 \quad[\because 12 \times 11 \times 10=1320]
\end{array}
$$
Looking for more such questions to practice?
Download the MARKS App - The ultimate prep app for IIT JEE & NEET with chapter-wise PYQs, revision notes, formula sheets, custom tests & much more.