RE: Find out which of the following number is not a perfect square.
a. 2187
b. 78125
c. 16284
d. 3125
e. None of the above
Thanks for asking question on GMAT Section,
Your question was – Find out which of the following number is not a perfect square.
Your correct answer is- A
Now read this explanation for more clarifications:
According to the standard properties of square numbers, all perfect square numbers must end in either 0, 1, 4, 5, 6 or 9.
Now, looking at the given options, we find that options b, c and d have 4 and 5 as the digit in the unit’s place.
Hence, these numbers belong to the set of perfect squares.
Thus, we are left only with the option a. this number has 7 as the digit in the unit’s place.
Hence, it 2187 is not a perfect square.
Hence, the correct answer is option a.