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If m parallel lines in a plane are int...

If `m` parallel lines in a plane are intersected by a family of `n` parallel lines, the number of parallelograms that can be formed is a. `1/4m n(m-1)(n-1)` b. `1/4m n(m-1)` c. `1/4m^2n^2` d. none of these

A

`""^(m-1)C_(2),""^(n-1)C_(2)`

B

`""^(m)C_(2)*""^(n)C_(2)`

C

`""^(m-1)C_(2)*""^(n)C_(2)`

D

`""^(m)C_(2)*""^(n-1)C_(2)`

Text Solution

Verified by Experts

The correct Answer is:
B
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