How many integral divisors does the number 120 have?a)14b)16c)12d)20e)...
Step 1 of solving this GMAT Number Properties Question: Express the number in terms of its prime factors
120 = 23 * 3 * 5.
The three prime factors are 2, 3 and 5.
The powers of these prime factors are 3, 1 and 1 respectively.
Step 2 of solving this GMAT Number Properties Question:Find the number of factors as follows
To find the number of factors / integral divisors that 120 has, increment the powers of each of the prime factors by 1 and then multiply them.
Number of factors = (3 + 1) * (1 + 1) * (1 + 1) = 4 * 2 * 2 =16
Choice B is the correct answer.
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How many integral divisors does the number 120 have?a)14b)16c)12d)20e)...
Solution:
To find the integral divisors of a number, we need to find all the positive integers that divide the number without leaving any remainder.
Prime Factorization of 120:
120 = 2^3 × 3 × 5
To find all the divisors of 120, we can use the prime factorization.
We can find all the divisors of 120 by choosing a combination of the prime factors 2, 3, and 5.
To find the number of divisors, we can use the following formula:
Number of divisors = (a+1) × (b+1) × (c+1) × …
where a, b, c, … are the powers of the prime factors in the prime factorization.
For 120, a=3, b=1, and c=1.
Therefore, the number of divisors of 120 = (3+1) × (1+1) × (1+1) = 4 × 2 × 2 = 16
Hence, the correct answer is option B, 16.