Shortcut Trick
In any set of n numbers, the average p must satisfy the condition: Smallest ≤ p ≤ Largest.
Given the smallest number is 27, we only know that p ≥ 27 and Largest ≥ 27.
Since the other numbers in the set and the total count n are unknown, both p and the largest number can take any value ≥ 27.
Neither p = 30 nor Largest = 54 is a mandatory condition for all possible sets.
∴ The correct answer is Neither I nor II.
Alternate Method
Given: Smallest number in the set = 27. Average = p.
Let the numbers be x1, x2, x3, ... , xn.
⇒ Smallest (x1) = 27.
⇒ Average (p) = (x1 + x2 + ... + xn) ÷ n.
Checking Statement I: p = 30.
⇒ If set is {27, 28, 29}, p = (27 + 28 + 29) ÷ 3 = 28. (p ≠ 30).
⇒ If set is {27, 33}, p = (27 + 33) ÷ 2 = 30. (p = 30).
⇒ Statement I is not always correct.
Checking Statement II: Largest = 54.
⇒ If set is {27, 28}, Largest = 28. (Largest ≠ 54).
⇒ If set is {27, 54}, Largest = 54. (Largest = 54).
⇒ Statement II is not always correct.
∴ The correct answer is Neither I nor II.
Additional Information
Range of Average
The arithmetic mean or average always lies between the minimum and maximum values of a data set: xmin ≤ p ≤ xmax.
Dependency on Number of Terms
To uniquely determine the average (p) or any specific term like the largest number, we must know the values of all other terms or specific properties of the distribution (like an AP).
Effect of Extremes
The average is highly sensitive to outliers. A very large maximum value will significantly pull the average p higher, regardless of the smallest value.