Problem 1: Data Sufficiency
If the integers a and n are greater than 1 and the product of the first eight positive integers is a multiple of a^n, what is a?
(1) a^n = 64
(2) n = 6
Problem 2: Problem Solving
At a dinner party, 5 people are to be seated around a circular table. Two seating arrangements are said to be different only when the positions of people are different relative to each other. What is the total number of different possible seating arrangements for the group?
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From the the question we know that A and N>1 and 8! is a multiple of a^N
8!=40,320.
Clue one tells us that a^N is 64-
40,320 divided by 64 leaves 630 which is which is equal to 2^1*5^1*7^1*3^2 so the prime factors of 40,320 are 2^7,3^2,5^1,3^2 so the only integer greater than raised to the power of another integer greater than 1 that can equal 64 and be a factor of 40,320 is 2 so the data is sufficient. Discard BCE and go with AD
Clue 2 tells us that n=6, and from the work above the only prime factor raised to a power 6 or greater is 2. so statement 2 is sufficient as well.
Answer D
Please correct me if I am wrong.
8!=40,320.
Clue one tells us that a^N is 64-
40,320 divided by 64 leaves 630 which is which is equal to 2^1*5^1*7^1*3^2 so the prime factors of 40,320 are 2^7,3^2,5^1,3^2 so the only integer greater than raised to the power of another integer greater than 1 that can equal 64 and be a factor of 40,320 is 2 so the data is sufficient. Discard BCE and go with AD
Clue 2 tells us that n=6, and from the work above the only prime factor raised to a power 6 or greater is 2. so statement 2 is sufficient as well.
Answer D
Please correct me if I am wrong.
- givemeanid
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8! (40,320) is a multiple of a^n
(1) 64 = 2^6 = 4^3 = 8^2 = a^n. Not sufficient.
(2) n = 6. Factorizing, 40320 = 2^6 * 2 * 3^2 * 5^1 * 7^1. So, a=2, n=6 is the only possibility.
Answer is (B)
(1) 64 = 2^6 = 4^3 = 8^2 = a^n. Not sufficient.
(2) n = 6. Factorizing, 40320 = 2^6 * 2 * 3^2 * 5^1 * 7^1. So, a=2, n=6 is the only possibility.
Answer is (B)
- givemeanid
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If this were not a circular arrangement, then the number of different possibilities would simply be 5! = 120.Problem 2: Problem Solving
At a dinner party, 5 people are to be seated around a circular table. Two seating arrangements are said to be different only when the positions of people are different relative to each other. What is the total number of different possible seating arrangements for the group?
With a circular arrangement for 5, it is equivalent of choosing from 4 people without a circular arrangement which is 4! = 24.
(To imagine this, in a circular arrangement, if the first person is seated at table 1, then we have 4! = 24 different combos that other people can be seated. But when you make person 2 sit at table 1, all those arrangements are still possible with person 1 sitting at table 1 anyway).
- givemeanid
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