Question

80,50, 71,59,55,75,?,100 what is ?

Answer 1

Answer:

50 , 59 , 75 , 100. Let's look the difference. 80 - 71 = 9. 71 - 55 = 16. 59 - 50 = 9.

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