Question: In a bucket there are 3 green balls and 2 yellow balls. What is the probability of drawing at least one green ball when drawing two consecutive balls randomly?
Options:
(A) 16/20
(B) 9/10
(C) 2/5
(D) 3/5
(E)
Answer: P(at least one green) = 1 - P(no green, so 2 yellow) = 1- 2/5*1/4 = 9/10.
The answer is (B).

Question: The average age of applicants for a new job is 10, with a standard deviation of 8. The hiring manager is only willing to accept applicants whose age is within one standard deviation of the average age. Assuming that all applicants' ages are integers and that the endpoints of the range are included, what is the maximum number of different ages of the applicants?
Options:
(A) 8
(B) 16
(C) 17
(D) 18
(E) 34
Answer: Minimum age = Average - 1 Standard deviation = 10 - 8 = 2
Maximum age = average + 1 Standard deviation = 10+ 8 = 18
Maximum number of different ages of the applicants = 18 - 2 + 1 = 17
The answer is (C).

Question: The average mark obtained by 22 candidates in an examination is 48. The average of the first ten is 55 while the last eleven is 40 .The marks obtained by the 11th candidate is ?
Options:
(A) 22
(B) 0
(C) 49
(D) 58
(E) 66
Answer: It is clear that 22 x 48 = 10 x 55 + K + 11 x 40 K = 66
The answer is (E).

Question: The average of first 18 even numbers is?
Options:
(A) 19
(B) 18
(C) 16
(D) 11
(E) 17
Answer:
Sum of 18 even numbers = 18 * 19 = 342
Average = 342/18 = 19
The answer is (A).