Chance can wash the car in 2 hours, while Sandy can wash the same car in 4 hours. How many hours would it take for them to wash
2 answers:
Answer: First Option is correct.
Step-by-step explanation:
Since we have given that
Number of hours Chance can wash the car = 2 hours
Number of hours Sandy can wash the car = 4 hours
Work done by Chance per hour is given by
Work done by Sandy per hour is given by
Work done by altogether per hour is given by
So, Number of hours they take if they together wash the car is given by
Hence, First Option is correct.
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Answer:
(a) 0.0256
(b) 0.2944
Step-by-step explanation:
For solving this exercise we can apply the binomial distribution. The equation that give as the probability is:
Where n is the number of identical events, p is the probability that the event has a success and x is the number of success in the n identical events.
Additionally, nCx is calculated as:
So, in this case we have 2 identical events because we are going to select two people randomly and the probability p of success is the probability that the person is allergic to pollen and this probability is 16%.
Then, for the first case, x is 2 because their are asking for the probability that both are allergic to pollen. Replacing the values of x, n and p we get:
P(2,2,0.16)=0.0256
For the second case, their are asking for the probability that at least one is allergic to pollen, that means that we need to sum the probability that both are allergic to pollen with the probability that just one is allergic to pollen.
Using the same equation to calculate P(1,2,0.16) we get:
P(1,2,0.16)=0.2688
So, the probability that at least one person is allergic to pollen is 0.2944 and it is calculated as:
0.0256 + 0.2688 = 0.2944