If x is a positive integer, is √(x) < 2.5 * (x - 5) ?
1) x < 3
2) x is a prime number
OA IS A. HOW TO DISPROVE STMNT 2
1) x < 3
2) x is a prime number
OA IS A. HOW TO DISPROVE STMNT 2
(1) x < 3 implies x can be either 1 or 2.pappueshwar wrote:If x is a positive integer, is √(x) < 2.5 * (x - 5) ?
1) x < 3
2) x is a prime number
OA IS A. HOW TO DISPROVE STMNT 2
If x = 1 then √x = 1 and 2.5 * (x - 5) = 2.5 * (1 - 5) = 2.5 * -4 = -10. Here √(x) > 2.5 * (x - 5)
If x = 2 then √x = √2 and 2.5 * (x - 5) = 2.5 * (2 - 5) = 2.5 * -3 = -7.5. Here also √(x) > 2.5 * (x - 5)
So, √(x) > 2.5 * (x - 5); SUFFICIENT.
(2) x is a prime number.
If x = 2, then √x = √2 and 2.5 * (x - 5) = 2.5 * (2 - 5) = 2.5 * -3 = -7.5. Here √(x) > 2.5 * (x - 5)
If x = 7, then √x = √7 and 2.5 * (7 - 5) = 2.5 * (7 - 5) = 2.5 * 2 = 5. Here √(x) < 2.5 * (x - 5)
No definite answer; NOT sufficient.
The correct answer is A.
