Question

$6$ parallel lines are intersected by $5$ other parallel lines.The total number of parallelograms formed is

• A. $150$
• B. $140$
• C. $120$
• D. $180$

Answer 1

The correct option is A $150$

There are $6$ parallel lines and $5$ parallel lines.

For forming parallelogram , we have to select any $2$ of $6$ parallel lines and select any $2$ from $5$ paralllel lines

${=}^6{C}_2{\times }^5{C}_2=150$