Answer:
36 blue jelly beans
Explanation:
We can find the total number of jelly beans by adding all red, yellow, and blue jelly beans together.
14+6+x
This simplifies to 20+x
For probability, it is (the number of things you want)/(the total number of things there are).
If the probably of drawing a yellow jelly bean is 1/4, we can set up this equation:

We can cross multiply:

There are 36 blue jelly beans.