akijuneja wrote:
A person was dialing a telephone. He forgot the last three digits of the six-digit telephone number but rembered that the number formed by the last three digits in the same order was a perfect square. What is the probability he dialed a right number?
(A) 1/32
(B) 1/46
(C) 1/49
(D) 1/36
(E) 1/18
Please explain.
(A) 1/32
(B) 1/46
(C) 1/49
(D) 1/36
(E) 1/18
Please explain.
There are following perfect squares less than 1,000:
000 (0^2);
001 (1^1);
004;
009;
016;
025;
036;
049;
064;
081;
100;
121;
144;
...
961 (31^2).
Total of 32 perfect squares.
The probability = 1/32.
Answer: A.