I'm learning about gear ratios in my engineering class! however, i need help unto understanding the concept of simplifying a gear train of more than two parts (in this case, three & two, but it'll help greatly if you have other examples in comparisons to the questions that i have here!)

note(s); the arrow '->' indicates where the input gear is. and the questions that i have left below, are to be in the 'x:x' format. again, if you want to bend it a little on how you are adjusted to it, then feel free, as long as you explain how you did it for me to comprehend, thank you in advance & stay safe.

QUESTIONs

1) ->8:32
a. 1:4
b. 4:1
c. 1:2
d. 2:1

2) ->40:8
a. 5:1
b. 1:5
c. 40:8
d. 20:4

3) ->16:24:40
a. 5:2
b. 2:5
c. 4:2
d. 5:3

4) ->40:8:24
a. 3:5
b. 5:3
c. 1:5
d. 6:7

->16:24:16
a. 1:1
b. 2:1
c. 2:2
d. 4:6

6) ->40:24:24
a. 3:5
b. 5:3
c. 1:6
d. 2:5