The average of five results is 46 and that of the first four is 45. The fifth result is__________?
A. 1
B. 10
C. 12.5
D. 50
Basic Arithmetic
Three years ago the average age of a family of six members was 19 years. A boy have been born, the average age of the family is the same today. What is the age of the boy?
A. 1 year
B. 1.5 years
C. 2 years
D. 2.5 years
Out of 15 consecutive numbers, 2 are chosen at random. The probability that they are both odds or both primes is_________?
A. 10/17
B. 10/19
C. 46/105
D. Cannot be determined
What is the probability that a leap year has 53 Sundays and 52 Mondays?
A. 0
B. 1/7
C. 2/7
D. 5/7
A box contains 3 blue marbles, 4 red, 6 green marbles and 2 yellow marbles. If two marbles are picked at random, what is the probability that they are either blue or yellow?
A. 3/22
B. 4/21
C. 2/21
D. 1/14
A bag contains five white and four red balls. Two balls are picked at random from the bag. What is the probability that they both are different color?
A. 4/9
B. 5/9
C. 7/9
D. 8/9
Three 6 faced dice are thrown together. The probability that no two dice show the same number on them is__________?
A. 7/12
B. 5/9
C. 1/36
D. 5/12
A box contains 3 blue marbles, 4 red, 6 green marbles and 2 yellow marbles. If four marbles are picked at random, what is the probability that none is blue?
A. 17/91
B. 33/91
C. 51/91
D. 65/91
A box contains 3 blue marbles, 4 red, 6 green marbles and 2 yellow marbles. If three marbles are picked at random, what is the probability that they are all blue?
A. 1/455
B. 2/455
C. 1/91
D. 4/455
Three 6 faced dice are thrown together. The probability that exactly two dice show the same number on them is -.
A. 5/9
B. 5/12
C. 1/36
D. 7/12