Question

A set of 4 parallel lines intersect with another set of 5 parallel lines. How many parallelograms are formed ?

• A.
  $20$
• B.
  $48$
• C.
  $60$
• D.
  $72$

Answer 1

The correct option is C

$60$
$Numberofparallelogram$

$={}^4{C}_2\times {}^5{C}_2$

$=6\times 10$

$=60$