Question

80,50,71,59,55,75,?,100
Options
20
40
30
90

Answer 1

$\huge\mathfrak{ANSWER:}$

Take the alternate numbers

80 , 71 , 55 , ?

50 , 59 , 75 , 100

Let's look the difference

80 - 71 = 9

71 - 55 = 16

59 - 50 = 9

75 - 59 = 16

100 - 75 = 25

so

55 - ? = 25

? = 30

Answer 2

ANSWER:

Take the alternate numbers

80 , 71 , 55 , ?

50 , 59 , 75 , 100

Let's look the difference

80 - 71 = 9

71 - 55 = 16

59 - 50 = 9

75 - 59 = 16

100 - 75 = 25

so

55 - ? = 25

? = 30