Bunuel
If \(n=k^2pr^3\) where k, p and r are different prime numbers what is the lowest possible value of n ?
A. 180
B. 240
C. 300
D. 360
E. 720
2 ways of doing this.
Method 1: If we want the lowest possible value of n, then the prime numbers have to be 2, 3 and 5.
Then we have 6 ways of putting the values of k, p and r and we get to the answer. A little application would help in the fact that the lowest value should be given to the number with the highest power. So if we take r = 2, k = 3 and p = 5, we get n = 9 * 5 * 8 = 720
Method 2:Break each of the Options into its factors to see which of them fits our requirements.
Option A: 180 = \(2^2 * 3^2 *5\). This is not possible as we need a cubic power.
Option B: 240 = \(2^4 * 3 *5\). This is not possible.
Option C: 300 = \(2^2 * 3 *5^2\). This is not possible as we need a cubic power.
Option D: 360 = \(2^3 * 3^2 *5\). This Fits our requirement.
No need to check Option E as it is greater than 360.
Option DArun Kumar