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Consider a series of 300 numbers in which the first number..
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29 Oct 2020, 22:38
29 Oct 2020, 22:38
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Consider a series of 300 numbers in which the first number is 3 and the second number is 5, and each succeeding number is equal to the sum of the previous two numbers in the series. If a number is randomly selected from the series, what is the probability that the number selected will be odd?
A. 1/3
B. 1/2
C. 2/3
D. 3/4
E. 4/5
A. 1/3
B. 1/2
C. 2/3
D. 3/4
E. 4/5
Re: Consider a series of 300 numbers in which the first number..
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30 Oct 2020, 02:17
30 Oct 2020, 02:17
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The series will look like this
3,5,8,13,21,34,55,89,144,233,377,600
Looking at the series above
Even number appear one in every three
Hence ans is 1/3 A
Posted from my mobile device
3,5,8,13,21,34,55,89,144,233,377,600
Looking at the series above
Even number appear one in every three
Hence ans is 1/3 A
Posted from my mobile device
Retired Moderator
Joined: 10 Apr 2015
Posts: 6218
Given Kudos: 136
Re: Consider a series of 300 numbers in which the first number..
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30 Oct 2020, 06:03
30 Oct 2020, 06:03
2
bunterocks wrote:
Consider a series of 300 numbers in which the first number is 3 and the second number is 5, and each succeeding number is equal to the sum of the previous two numbers in the series. If a number is randomly selected from the series, what is the probability that the number selected will be odd?
A. 1/3
B. 1/2
C. 2/3
D. 3/4
E. 4/5
A. 1/3
B. 1/2
C. 2/3
D. 3/4
E. 4/5
As always, let's list a few terms in the series.
However, since all we care about is EVEN and ODD, we'll replace 3 with ODD and replace 5 with ODD
We get:
term1 = 3 = ODD
term2 = 5 = ODD
term3 = ODD + ODD = EVEN
term4 = EVEN + ODD = ODD
term5 = ODD + EVEN = ODD
term6 = ODD + ODD = EVEN
term7 = EVEN + ODD = ODD
term8 = ODD + EVEN = ODD
term9 = ODD + ODD = EVEN
We can see that the pattern ODD - ODD - EVEN repeats every three terms.
So, P(ODD) = 2/3
Answer: C
Cheers,
Brent
