what is the probability of getting a sum of 5 before 7 when 3 dice are thrown?

• 2/7 ans......
  P(5)=6/216 , P(7)= 15/216 , P(other than 5 or 7 )=195/216
  the series would be 6/216 + (195/216)*(6/216) + (195/216)^2 * (6/216) + ..........
  on solving this GP ....ans will be 2/7
  
• 11 years agoHelpfull: Yes(20) No(12)
• probability of getting sum 5 is 6 when 3 dices are rolled
  and probability of getting sum 7 is 15..
  so, here question asked before getting 7 the probability should be 6/15
• 11 years agoHelpfull: Yes(15) No(5)
• when three dails are rolled
  total no.of outcomes where the sum is 5=6ways[(1,3,1)=3ways+(1,2,2)=3ways]
  total no.of outcomes where sum is 7=12ways[(1,5,1)=3ways+(2,4,1)=6ways+(3,3,1)=3ways]
  probability of getting sum of 5 before 7=6/(6+12)=6/18=1/3
• 11 years agoHelpfull: Yes(8) No(7)
• possibilty of getting 5 is 6 so probability is 6/216=1/36
• 11 years agoHelpfull: Yes(4) No(6)
• i found 2/3
• 11 years agoHelpfull: Yes(3) No(5)
• possibility of getting 5 is 12 which is 1,2,2(3!) and 1,1,3(3!)
  and total outcome is 216(6*6*6)
  18/216
• 11 years agoHelpfull: Yes(2) No(27)
• dekh 5 hote pare when x1+x2+x3=5 and x1,x2,x3>=1
  
  tahole etake likhbo, (x1-1)+(x2-1)+(x3-1)=3 or, y1+y2+y3=3
  
  where, y1,y2,y3>=0
  
  no. of solution 4C2
  
  prob= 4C2/216
  
  similarly, prob(7)=6C2/216
  
  to 7 er age 5 asar prob = P(5)+(1-P(5)-P(7))P(5)+(1-P(5)-P(7))^2*P(5)+....
• 11 years agoHelpfull: Yes(2) No(12)
• final answer 2/5
• 11 years agoHelpfull: Yes(2) No(1)
• In 6 ways we get 5 & in 12 ways we get 7.Getting 5 and 7 are two independent event.So, the probability will be 6/18=1/3.
• 11 years agoHelpfull: Yes(1) No(2)