Q. 10 friends meet for movie 20 for picnic and 5 for games 4 for movie & picnic 2 for movie & games, 0 for picnic & games, 2 for all, how many are students are there in all?

• n(A U B U C)=n(A) + n(B) + n(C) - n(A INTERSECTION B) - n(A INTERSECTION C) - n(C INTERSECTION B) + n(A INTERSECTION B - INTERSECTION C)
  Hence,
  Total no. of Students = 10 + 20 + 5 - 4 - 0 - 2 + 2
  = 31.
• 12 years agoHelpfull: Yes(56) No(4)
• answer is 31.
  10+20+5-4-2-0+2=31.
  
• 12 years agoHelpfull: Yes(7) No(2)
• its 31 as we use the formulae n(A U B U C)
  at few places its answer is given as 25 using set theory but this is correct.
  
• 12 years agoHelpfull: Yes(2) No(1)
• only movie 10-4-2=4
  only picnic 20-4=16
  only games 5-2=3
  total std=4+16+3+2=25
• 12 years agoHelpfull: Yes(1) No(7)
• Total no. of Students = 10 + 20 + 5 - 4 - 0 - 2 + 2
  = 31.
• 8 years agoHelpfull: Yes(1) No(1)
• 10+20+5-4-2-0+2=31
• 10 years agoHelpfull: Yes(0) No(0)