Q. What is the next number of the following sequence.
7,-14,-4,15,-30,-20,-21,.........

• Series runs by *-2,+10 sequentially
  7*-2=-14, -14+10=-4
  15*-2=-30, -30+10=-20
  Similarly, -21*-2=42, 42+10=52
  Next Series numbers are 42,52
• 11 years agoHelpfull: Yes(17) No(0)
• 7 (-2) = 14...-4
  15(-2) = 30...-4(5)
  21(-2) = x
  
  x = 42
• 11 years agoHelpfull: Yes(2) No(0)
• -42 is the answer
• 10 years agoHelpfull: Yes(1) No(1)
• 7*-2=-14, -14+10=-4
  15*-2=-30, -30+10=-20
  similarly
  -21*-2=42, 42+10=52
  ans 52
  
• 11 years agoHelpfull: Yes(0) No(0)
• 7*(-2)=-14
  -14+10=-4
  Again 15*(-2)=-30
  -30+10=-20
  in the same way -21*(-2)=42
  and 42+10=52
  hence the series is 7,-14,-4,15,-30,-20,-21,42,52
• 11 years agoHelpfull: Yes(0) No(0)