Suppose you know a/b = 24%, it may be that b=21 since 5/21 = .238095... but b could not be 22 since 5/22=23% and 6/22=27%.

Still using 24%:

[1] What is the smallest possible value of b?

[2] What is the largest value that b could not be?

Now find the 5 percentages between 0 and 50

[3] that give the largest answers to part [1]?

[4] that give the smallest answers to part [2]?