There is a row of 81 children of which 2 of them are girls. They are standing in an
initial order such that a set of 9 boys, who are gadget freaks, stand next to each other in a
certain order. Now, the positions of boys and girls are shuffled such that, the order of girls
remain the same, the gadget freaks are together in the same order, but the position and of
remaining boys are changed. How many distinct arrangements of the students can be done
(including the initial order) by preserving the order of girls and keeping the gadget freaks
together?
A. 72!
B. 71!
C. 71! * 2556
D. 72!* 2556

• Ans is 72!
  since gadget freaks and the girls will not have any change in order within themselves ,
  so, we have 70 remaining boys and 1 Gadget freaks group and 1 girls group
  or, 70+1+1 = 72 positions to have their order interchanged
  
  formula for this is 72P72 = 72!
• 10 years agoHelpfull: Yes(12) No(2)
• A.72!
  9 gadget freaks and 2 girls are considered single entity ..hence {(9),(2),70!}=72!
• 10 years agoHelpfull: Yes(4) No(8)
• (70+1+1)!=72!
• 10 years agoHelpfull: Yes(1) No(1)
• 72!
  81-11=70
  70+1+1=72
  
  hence 72!
• 10 years agoHelpfull: Yes(0) No(1)