Just find their greatest common factor and divide both the numbers by it.
Answers:
35:45 is divisible by 9 = 4:5
4:96 is divisible by 4 = 1:24
10:95 is divisible by 5 = 2:19
45:30 is divisibpe by 15 = 3:2
91:63 is divisible by 7 = 13:9
1000:120 is divisible by 40 = 25:3
75:25 is divisible by 25 = 3:1
