Look at this series: 53, 53, 40, 40, 27, 27, ... What number should come next?

• 12

• 14

• 27

• 53

Look at this series: F2, __, D8, C16, B32, ... What number should fill the blank?

• A16

• 
  G4

• 
  E4

• E3

Look at this series: 21, 9, 21, 11, 21, 13, 21, ... What number should come next?

• 14

• 15

• 21

• 23

Look at this series: 100, 90, 80, 70, ... What number should come next?

• 70

• 60

• 50

• 40

Look at this series: A1, B2, C3, D4, ... What should come next?

• E5

• A2

• D5

• F6

Look at this series: 5, 10, 15, 20, ... What number should come next?

• 25

• 15

• 20

• 30

Look at this series: 2, 4, 8, 16, ... What number should come next?

• 18

• 20

• 24

• 32

Look at this series: 1, 1, 2, 3, 5, ... What number should come next?

• 9

• 8

• 6

• 7

Look at this series: Z1, Y2, X3, W4, ... What should come next?

• T6

• V5

• U5

• W5

Look at this series: 3, 6, 12, 24, ... What number should come next?

• 60

• 72

• 48

• 36