Alphonsaj wrote:In how many ways can 480 be expressed as a product of two positive integers that are relatively prime (co-prime) to each other?
A) 24
B) 12
C) 4
D) 8
E) 2
Co-primes are integers that have no factors in common other than 1.
The prompt should make clear that xy and yx are to be considered the same product.
480 = (2�)(3)(5).
From the prime-factorization above, we can form the following factor pairs that have a product of 480 and are co-primes:
(1)(2�3*5)
(2�)(3*5)
(3)(2�5)
(5)(2�3).
Total ways = 4.
The correct answer is
C.
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