Look at this series: 31, 29, 24, 22, 17, ... What number should come next?
a)15
b)14
c)13
d)12

• 15
  First number is 31
  2nd number is 29 (31 -2)
  3rd number is 24 (29 -5)
  4th number is 22 (24 -2)
  5th number is 17 (22 -5)
  6th number is 15 (17 -2)
• 13 years agoHelpfull: Yes(7) No(0)
• 15
  
  as difference of terms is 2,5,2,5,2 ......
• 13 years agoHelpfull: Yes(2) No(1)
• since the difference of series is 2,5,2,5.so next term will be as 17-2=15.
• 10 years agoHelpfull: Yes(2) No(0)
• 15
  alternative difference is 2,5,2,5....
  
• 9 years agoHelpfull: Yes(1) No(0)
• 15
  31-2=29
  29-5=24
  24-2=22
  22-5=17
  17-2=15
• 9 years agoHelpfull: Yes(0) No(0)
• DIFFERENCE B/W ODD AND EVEN PLACE IS 7 SO AFTER 17 ,IS 15
  
• 9 years agoHelpfull: Yes(0) No(0)
• ans 15
  first seqence 31,24,17
  second seqence 29,22,?..
  first sequence 31-7=24
  ..........................24-7=17
  second sequence 29-7=22
  .............................22-7=15
• 6 years agoHelpfull: Yes(0) No(0)
• 31-29=2
  29-24=5,24-22=2,22-17=5
  so 17-2=15
• 6 years agoHelpfull: Yes(0) No(0)
• 15
  First number is 31
  2nd number is 29 (31 -2)
  3rd number is 24 (29 -5)
  4th number is 22 (24 -2)
  5th number is 17 (22 -5)
  6th number is 15 (17 -2)
• 6 years agoHelpfull: Yes(0) No(0)