Answer:
There is a 99.99998% probability that at least one valve opens.
Step-by-step explanation:
For each valve there are only two possible outcomes. Either it opens on demand, or it does not. This means that we use the binomial probability distribution to solve this problem.
Binomial probability distribution
The binomial probability is the probability of exactly x successes on n repeated trials, and X can only have two outcomes.
In which 
is the number of different combinatios of x objects from a set of n elements, given by the following formula.
And p is the probability of X happening.
In this problem we have that:
Calculate P(at least one valve opens).
This is 
Either no valves open, or at least one does. The sum of the probabilities of these events is decimal 1. So:
So
Finally
There is a 99.99998% probability that at least one valve opens.
The significant components, the radius and the height, are in inches and feet respectively, you'd need to convert them both to the same unit, whichever it may be, meters or feet or inches or millimeters, so long is the same, then use the volume of a cylinder equation to get it.
When you get to the point where the width is larger than the length, you can stop because you have exhausted all the possibilities. The greatest area will be the rectangle that is closer in to a square than any of the others.
Answer: 7 laps
Step-by-step explanation:
The athlete planned to run 3 miles
1 lap = 3/7 miles
x laps = 3 miles
by proportion :
x × 3/7miles = 3 miles
x = 3 ÷ 3/7
x = 3 x 7/3
x = 7
Therefore: the athlete will run 7 laps
