If each term in the sum a1+a2+a3+...+an is either 7 or 77 and the sum equals 350, which of the following could be equal to n?A.
1 answer:
Answer:
C. 40
Step-by-step explanation:
Let us say there are x 7's and y 77's.
We have been given that each term in the sum a1+a2+a3+...+an is either 7 or 77 and the sum equals 350. We are asked to find the value of n.
Since the sum of all numbers is 350, so we can represent this information in an equation as:
The only integer solutions for the equation are 10, 20, 30, 40, 50
.
So, there can be these many terms: 10 or 20 or 30 or 40 or 50 .
The given option only contains 40, so 40 would be the answer. For 40 terms to be there, there has to be 39 sevens and 1 seventy-seven.
Let us verify our answer.
Therefore, the total terms (n) could be equal to 40 and option C is the correct choice.
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Answer:
a)0,45119
b)1
Step-by-step explanation:
For part A of the problem we must first find the probability that both people in the couple have the same birthday (April 30)
Now the poisson approximation is used
λ=nP=80000*1/133225=0,6
Now, let X be the number of couples that birth April 30
P(X ≥ 1) =
1 − P(X = 0) =
P(X ≥ 1) = 0,45119
B) Now want to find the
probability that both partners celebrated their birthday on th, assuming that the year is 52 weeks and therefore 52 thursday
Now the poisson approximation is used
λ=nP=80000*52/133225=31.225
Now, let X be the number of couples that birth same day
P(X ≥ 1) =
1 − P(X = 0) =
P(X ≥ 1) = 1