25% of the 200 jelly beans are green, by converting 25% into a decimal and multiplying it by the total amount of jelly beans, you can find the amount of jelly beans that are green.
25% = 0.25
200 x 0.25 = 50
Therefore 50 of the jelly beans are green.
The question wants to know the probability of the jelly bean being picked is not green.
You just add the values for volunteers that worked 16-20 hours and 21-25 hours which would be 50 + 10 = 60. So the total number of volunteers that workers more than 15 hours is 60.
