Find the next number
12,36,85,184,383,782,?,3180

a)1579 b)1578 c)1581 d)1583

• Answer: c)1581
  solution:to take the differece between each number
  so, first difference =24,49,99,199,399
  after to take differece from Ist difference
  second difference=25,50,100,200
  in this second difference we get the next number is 400
  
  2nd difference =25,50,100,200,400
  1st difference=24,49,99,199,399,799(i.e.,400+399=799)
  answer sequnce=12,36,85,184,383,782,1581(i.e.,799+782=1581)
• 13 years agoHelpfull: Yes(2) No(1)
• Answer is c)1581
  
  This sequence made up of multiple by 2 with previous number and added with 12,13,14,15,16,17,18 and so on..)
  see the below explanation
  12, 36(12*2+12), 85(36*2+13), 184(85*2+14), 383(184*2+15), 782(383*2+16), 1581(782*2+17), 3180(1581*2+18)..
  
• 13 years agoHelpfull: Yes(1) No(0)
• c)1581.
  
  12,36,85,184,383,782,?,3180
  difference=24,49,99,199,399....
  i.e. 2k-1 where k=25,50,100,200,400,800....
  So, the next difference will be 799.
  Adding 799 & 782, giving the answer as 1581.
  For counter checking now, 2k-1. Substitute k=800 results 1599. Add 1599 with the result 1581 i.e. 3180. Hence the answer 1581 is correct.
• 13 years agoHelpfull: Yes(0) No(1)
• ans c)1581
  36 - 12 = 25-1
  85 - 36 = 50-1
  184 - 85 = 100-1
  383 - 184 = 200-1
  782 - 383 = 400-1
  1581 - 782 = 800-1
  3180 -1581 =1600-1
  
  
• 13 years agoHelpfull: Yes(0) No(0)