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:



- 4 1/3 = -(4*3+1)/3 =-13/3
-2 3/5 = -(5*2+3)/5 = -13/5
-13/3 divided by -13/5
-copy dot flip
-13/3 *-5/13
5/3
1 2/3
Choice A
<span>10<span>(<span><span>122<span>(13)</span></span><span>(12)</span></span>)</span></span><span>=<span><span>10<span>(122)</span></span><span>(156)</span></span></span><span>=<span><span>(10)</span><span>(19032)</span></span></span><span>=<span>190320
Hope You understand
This is just basic multiplication.</span></span>