40.
80
22
It is possible to find a quartic equation (power 4) so that any fifth number is the next in the sequence. The cubic that fits these is Un = (n3 + 17n + 30)/6 for n = 1, 2, 3, ... and therefore, the next term is 40.
Double it every time and so the next number will be 80
If you mean: 5 10 20 40 then it is 80
40 5 10 20 40 80 160.......double the number each time.
16
The pattern is to divide by 5, so the next number would be 40
The next number should be 80.
If the last number is 1/3 (it should be), the next number is 5 and 1/3
70