The ratio in it's simplest form is 4:1.
If you are rolling a single six sided die numbered 1-6, you find that only 1,2,4, and 5 are factors of 20. Now the theoretical probability of an event is the ratio comparing the number of desired outcomes to the total outcomes possible.
In this case: we have 4 desired outcomes out of a total 6 outcomes possible with a single roll the die.. therefore, the probability you seek is

or approximately 67%.
Answer:
17 units
Step-by-step explanation:
Distance between points
is given by 
The trail starts at P(−2, 2) and goes to Q(5, 2).
Take 
units
It goes from Q to R(5, −5)
Take 
units
It goes from R to S.
Take 
units
units