there is four light.all light glow in blue,white,yellow and red.
all glow together and take different color.every time each light change its color in given four of the color.but at same time no two light have same color then tell how many design will form? Choose the correct choice from the following answers.
A) 20  B) 24  C) 18  D) 16  E) 22
it is so simple,it is just permutation of 4 item.   4P4=4!=24   answer 24
<result>B</result>
there is four light.all light glow in blue,white,yellow and red.
all glow together and take different color.every time each light change its color in given four of the color.but at same time no two light have same color then tell how many design will form?