Question 842485
Hi,

Firstly this is not sequences and series, simply asking you to find the next number.

Attempt to find the difference betweeen the numbers
7 -3 = 4
17-7 = 10
39-17 = 22
85-39 = 46

Calculate the differences between: 10-4 = 6 , 22-10 = 12 , 46- 22 = 24 (Notice the pattern!!!!)

Therefore since the difference is being multiplied by 2, your next number's difference will be 48

So 85+ 48 = 133