GMAT Math Ultimate Exam Questions with Correct Answers.

Common Factors Correct Answer Break down both numbers to their prime factors to see what factors they have in common. Multiply all combinations of shared prime factors to find all common factors. Gross Profit Correct Answer Gross profit = Selling Price - Cost Combined Events Correct Answer For events E and F: • not E = P(not E) = 1 - P(E) • E or F = P(E or F) = P(E) + P(F) - P(E and F) • E and F = P(E and F) = P(E)P(F) Multiplication Principle Correct Answer The number of ways independent events can occur together can be determined by multiplying together the number of possible outcomes for each event. 1st Rule of Probability: Likelihood of A Correct Answer Basic rule: The probability of event A occurring is the number of outcomes that result in A divided by the total number of possible outcomes. 2nd Rule of Probability: Complementary events Correct Answer Complementary Events: The probability of an event occurring plus the probability of the event not occurring = 1. P(E) = 1 - P(not E) 3rd Rule of Probability: Conditional Probability Correct Answer Conditional Probability: The probability of event A AND event B occurring is the probability of event A times the probability of event B, given that A has already occurred. P(A and B) = P(A) × P(B|A) 4th Rule of Probability: Probability of A OR B Correct Answer The probability of event A OR event B occurring is: the probability of event A occurring *plus* the probability of event B occurring *minus* the probability of both events occurring. P(A or B) = P(A) + P(B) - P(A and B) Probability of Multiple Events Correct Answer Rules: • A *and* B A *or* B • A *or* B Individual probabilities of A, B • P(A and B) = P(A) x P(B) ← "fewer options" • P(A or B) = P(A) + P(B) ← "more options"