How many distinct integers are factors of 90?
A) 6
B) 8
C) 9
D) 10
E) 12
OA: E
Solution:
Approach 1: List down the factors. 1, 2, 3, 6, 5, 9, 10, 15, 30, 45, 90 = 12
Approach 2: I just learnt about this method. So I thought I'd share it with you'll.
Prime factorization of 90 = 2^1 * 3^2 * 5^1
Now, we add 1 to each exponent and multiply them.
(1+1) * (2+1) * (1+1) = 12
It works with any number. I tried it. Let's take the example of 50. It's factors are 1, 2, 5, 10, 25, 50 = 6
or 2^1 * 5^2 = (1+1) * (2+1) = 6
I'm quite weak with math, so I thought I'd share it with others like me. Hope it helped
A) 6
B) 8
C) 9
D) 10
E) 12
OA: E
Solution:
Approach 1: List down the factors. 1, 2, 3, 6, 5, 9, 10, 15, 30, 45, 90 = 12
Approach 2: I just learnt about this method. So I thought I'd share it with you'll.
Prime factorization of 90 = 2^1 * 3^2 * 5^1
Now, we add 1 to each exponent and multiply them.
(1+1) * (2+1) * (1+1) = 12
It works with any number. I tried it. Let's take the example of 50. It's factors are 1, 2, 5, 10, 25, 50 = 6
or 2^1 * 5^2 = (1+1) * (2+1) = 6
I'm quite weak with math, so I thought I'd share it with others like me. Hope it helped
