Question
An instructor has a question bank consisting of 200 easy
True / False questions, 300 difficult True / False questions, 400 easy multiple-choice questions and 500 difficult multiple-choice questions. If a question is selected at random from the question bank, what is the probability that it will be an easy question given that it is a multiple-choice question?Solution
Let us denote E = easy questions, M = multiple choice question, D = difficult questions and T = true/false questions. Total number of questions = 1400 Total number of multiple-choice questions = 900 Probability of selecting easy multiple-choice question is P ( E ∩ M) = 400/1400 = 2/7 Probability of selecting multiple is P ( M) = 900/1400 = 9/14 P(E|M) represents the probability that a randomly selected question will be an easy question, given that is a multiple-choice question.  Therefore, P(E|M) = P( E ∩ M)/P(M) = (2/7)/(9/14) = 4/9 Therefore, required probability = 4/9
230 192 172 ? 122 100
...What value should come in the place of (?) in the following number series?
64, 80, 104, ?, 176, 224
97, 106, ?, 195, 411, 460
What will come in place of the question mark (?) in the following series?
29, 42, ?, 95, 135, 184
Find the missing term:
2, 6, 15, 31, 56, ?
32   48   96   ?   720   2520
82, 98, 130, 178, 242, ?
4 10 ? 62.5 156.25 390.625
...140, 146, 170, 224, ?, 470
7 47 ? 223 359 527
...
Relevant for Exams:
