Solve:-
111 x 111 x 111 + 555 x 555 x 555 = ?(111 x 111 - 111 x 555 + 555 x 555)
Options:
(A) 888
(B) 666
(C) 555
(D) 988
(E) 889
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Given Exp. = (a3 + b3) = (a + b) = (111 + 555) = 666 (a2 - ab + b2) So the answer is: (B).
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A password for a computer is six digits from 0 and 9. The six digit number is a prime number. What is the approximate probability that the last digit is a 3?
Options:
(A) 1/4
(B) 1/6
(C) 1/10
(D) 1/20
(E) 1/50
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If the last digit is 0, 2, 4, 6, or 8, the number is even and therefore not prime. If the last digit is 5, the number is divisible by 5 and therefore not prime. The only possibilities are 1, 3, 7, and 9. So the probability is approximately 1/4 (answer A). We say approximately because there is a certain degree of randomness in the distribution of prime numbers. So the answer is: (A).
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How many terminating zeroes Q does 200! have?
Options:
(A)  40
(B)  48
(C)  49
(D)  55
(E)  64
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You have 40 multiples of 5, 8 of 25 and 1 of 125. This will give 49 zeros. So the answer is: (C).
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