Find out the wrong number in the following series:
5, 15, 30, 80, 180, 540, 1080

• 80
  there should be a 90
  so we can have a series
  5, 5*3, 15*2, 30*3, 90*2, 180*3, 540*2 and 1080*3 and so on...
• 13 years agoHelpfull: Yes(40) No(2)
• 80 is wrong it should be 90
  5 30(5*6) 180(30*6) 1080(180*6) and
  15 90(15*6) 540(90*6) ....
  so combined mix series is= 5 15 30 90 180 540 1080 ....
  so ans is 80
  
• 13 years agoHelpfull: Yes(10) No(1)
• 80
  because pattern is
  *3,*2,*3,*2,*3,*2
• 12 years agoHelpfull: Yes(9) No(1)
• Ans. is 80; 5*6=30,30*6=180,180*6=1080. The same way 15*6=90,90*6=540. Here, instead of 90, the no. 80 is placed as wrong...
• 13 years agoHelpfull: Yes(4) No(0)
• 80..it shud b 90 to provide a correct sequence..
  
  15/3=3
  30/15=2
  ....90/30=3
  ....180/90=2
  540/180=3
  1080/540=2
• 12 years agoHelpfull: Yes(3) No(1)
• 80
  there should be a 90
  so we can have a series
  5, 5*3, 15*2, 30*3, 90*2, 180*3, 540*2 and 1080*3 and so on...
• 12 years agoHelpfull: Yes(2) No(0)
• 80 will be replaced by 90. because its multiplication of 6 every alternate number.
  like... 5*6=30, same as 15*6= 90... etc..
• 10 years agoHelpfull: Yes(1) No(1)
• 80 is wrong no.
  bcoz 5*3=15 15*2=30
  lykwise 30*3=90 90*2=180
  180*3=540 540*2=1080
  so 80 is wrong no because we r continously multipying by 3 and 2
• 11 years agoHelpfull: Yes(0) No(0)
• ans=80
  replace by 90 to form a correct series.
  5*6=30
  30*6=180
  180*6=1080
  15*6=90
  90*6=540
• 11 years agoHelpfull: Yes(0) No(0)
• the series should be as follows:
  5, 15, 30, 80, 160, 540, 1080
• 10 years agoHelpfull: Yes(0) No(0)
• 80
  5*6=30,30*6=180,180*6=1080
  15*6=90,90*6=540
• 10 years agoHelpfull: Yes(0) No(0)
• 80 is wrong ,it should be 90..
• 10 years agoHelpfull: Yes(0) No(0)
• answer is 8. 5*3=15 and 15*2=30 now 30*3=90 but we have 80.suppose it was 90 then 90*2=180 and so on.therefore 80
• 10 years agoHelpfull: Yes(0) No(0)
• 80
  5*3=15 -> 5,15
  15*2=30 -> 15,30
  30*3 = 90 -> 30,90
  90*2 =180 -> 90,180
  180*3 =540 ->180,540
  540*2=1080-> 540,1080
  5,15,30,90,180,540,1080
  
• 10 years agoHelpfull: Yes(0) No(0)