1, ?, 4, 7, 7, 8, 10, 9, ?

a)6
b)3
c)11
d)13
e)12

• given series is 1,?,4,7,7,8,10,9
  the alternative serieses are 1,4,7,10(adding+3)
  next ?,7,8,9 then the starting letter is 6 so optin (a) is ans
• 13 years agoHelpfull: Yes(8) No(1)