The first thing to do is to turn 5 into a fraction.
5 = 5/1
Now it is just a simple fractional division question:
3/4 / 5/1
With fractional division, all you do is switch around the fraction that is on the right and turn the divide sign into a multiplication sign:
3/4 X 1/5
Now you simply multiply the numerators together, and the denominators together:
3 X 1 = 3
4 X 5 = 20
3/20.
Each flower bed will contain 3/20 of a ton of mulch.