Since the sum of the probabilities of all possible outcomes must be 100%, we can deduce the following:
- Cooking in under 20 minutes: 10%
- Cooking between 20 and 30 minutes: 85%
- Cooking in more than 30 minutes: 5%
In fact, the probabilities of cooking in less than 20 or more than 30 sum up to 15%, which means that the remaining outcome (i.e. cooking time between 20 and 30) must complete this probability to 15, and in fact 15+85=100.
That being said, all three answers are simply a combination of these three scenarios: let C be the cooking time, for aesthetic reasons:



1/2 - 2/15= 15-4/30 = 11/30 this means that if you were to add 11/30 to 2/15 is exactly equal to 1/2, to fully answer your question you can use any value above that like 12/30 (keep in mind you have to simplify) = 6/15 = 2/5. But then again your question says to add any number to make it greater than 1/2 so technically you could just add 100 or 200 or 1/2 to make the sum of it greater than one half
(960-680)+d= total profit
960-680= 280 dollars of total profit
280× 186 days (six months and six days)= 52,080
So in six months and six days the store will become profitable.
There is no question stated!