Ask Questions, Get Answers

Want to ask us a question? Click here
Browse Questions
Home  >>  CBSE XI  >>  Math  >>  Permutations and Combinations
0 votes

The number of parallelogram that can be formed from a set of four parallel lines intersecting another set of three parallel lines is

$\begin{array}{1 1}(A)\;6\\(B)\;18\\(C)\;12\\(D)\;9\end{array} $

Can you answer this question?

1 Answer

0 votes
Total no of parallel lines =4
Intersecting lines =3
$\therefore$ The required number of parallelogram =$4C_2\times 3C_2$
$4C_2=\large\frac{4!}{2!2!}=\frac{4\times 3\times 2!}{2\times 2!}$
$\Rightarrow 6$
$3C_2=\large\frac{3!}{2!1!}=\frac{3\times 2!}{2!}$
$\Rightarrow 3$
$4C_2\times 3C_2=6\times 3$
$\Rightarrow 18$
Hence (B) is the correct answer.
answered May 16, 2014 by sreemathi.v

Related questions

Ask Question
student study plans
JEE MAIN, CBSE, NEET Mobile and Tablet App
The ultimate mobile app to help you crack your examinations
Get the Android App