2. PB and J Array Ken has made a selection of square jam sandwiches for party, which he arranges in a single layer on the table
in perfect rectangle. Sarah has brought along the same number of square peanut butter sandwiches, which she puts out, also as a single layer, to form a border vA (one sandwich wide) around Ken's Given that all of the sandwiches are the same size and they are all used, how many sandwiches could each person possibly have made?
2 answers:
Let's assume Ken arranged his sandwiches in a rectangular shape with length 'L' and width 'W'. Now Sarah arranged her sandwiches to form a border around Ken's rectangle. The solution diagram is attached below.
Ken needs as much sandwiches as area of rectangle i.e. number of Ken's sandwiches would be = LW.
It is clear that Sarah needs as much sandwiches as perimeter of rectangle and extra four sandwiches to put on corners. It means number of Sarah's sandwiches would be = 2·(L+W) + 4.
Given that all of the sandwiches are the same size and they are all used.
Ken and Sarah bought same number of sandwiches. So we need to solve the following equation :-
Number of Ken's sandwiches = Number of Sarah's sandwiches
LW = 2·(L+W) + 4
Using trial and error approach, we get 6 x 4 = 2 x (6 + 4) + 4.
So number of Ken's sandwiches would be LW = 6 x 4 = 24 sandwiches.
Hence, final answer is "Each person could have 24 sandwiches".
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Answer:
a) 9.52% probability that, in a year, there will be 4 hurricanes.
b) 4.284 years are expected to have 4 hurricanes.
c) The value of 4 is very close to the expected value of 4.284, so the Poisson distribution works well here.
Step-by-step explanation:
In a Poisson distribution, the probability that X represents the number of successes of a random variable is given by the following formula:
In which
x is the number of sucesses
e = 2.71828 is the Euler number
is the mean in the given time interval.
6.9 per year.
This means that
a. Find the probability that, in a year, there will be 4 hurricanes.
This is P(X = 4).
So
9.52% probability that, in a year, there will be 4 hurricanes.
b. In a 45-year period, how many years are expected to have 4 hurricanes?
For each year, the probability is 0.0952.
Multiplying by 45
45*0.0952 = 4.284.
4.284 years are expected to have 4 hurricanes.
c. How does the result from part (b) compare to a recent period of 45 years in which 4 years had 4 hurricanes? Does the Poisson distribution work well here?
The value of 4 is very close to the expected value of 4.284, so the Poisson distribution works well here.