If 3<x< 100, for how many values of x is x/3 the square of a prime number?
A) 2
B) 3
C) 4
D) 5
E) 9
Thank you,
Prerna
A) 2
B) 3
C) 4
D) 5
E) 9
Thank you,
Prerna
We want values of x (where 3 < x < 100) such that x/3 is the square of a prime number.prernamalhotra wrote:If 3<x< 100, for how many values of x is x/3 the square of a prime number?
A) 2
B) 3
C) 4
D) 5
E) 9
So, let's start checking squares of prime numbers.
Some prime numbers are 2, 3, 5, 7, 11, etc
2² = 4 and (3)(4) = 12. So, x = 12 meets the given conditions.
3² = 9 and (3)(9) = 27. So, x = 27 meets the given condition12
5² = 25 and (3)(25) = 75. So, x = 75 meets the given conditions.
7² = 49 and (3)(49) = 147. No good. We need values of x such that 3 < x < 100
So, there are exactly 3 values of x that meet the given conditions.
Answer: B
Cheers,
Brent
