# Shared Flashcard Set

## Details

GMAT - Applied Arithmetic
Rate, Work, Functions, Probabilities, Permutations, and Combinations
12
Mathematics
02/25/2009

Term
 Problems that mention planes, trains, bicycles, distance, mph (rate), and travel terminolgy
Definition
 Use formula rate x time = distance
Term
 Work Problems that involve two people or machines working at different rates
Definition
 Do not think about how long it takes to do the entire job, but rather how much of the job can be done in one hour.   Then set that fraction equal to 1/x, so a/b(fraction of job done in 1 hour) = 1/x
Term
 "Function" Problems containing strange symbols(\$ or # or * or "delta" or factorials "x!")
Definition
 Basically a set of directions.  First half of problem tells you how to treat the numbers in the second part.
Term
 Factorials "x!" 5! = ...
Definition
 = 5 x 4 x 3 x 2 x 1=120
Term
 Probability - Basic
Definition
 Put total number of possibilities in the denominator, and the number of possibilities that your are looking for in the numerator.
Term
 Probability - One Thing OR Another Probability of either one thing OR another thing happening
Definition
 Simply add the probabilites.Figure out the probability of the first scenario happening.  Then figure out the probability of the second scenario happening.Ex1/18 + 3/18 = 4/18 = 2/9
Term
 Probability - Odds That Something Doesn't Happen
Definition
 Figure out the probability that it WILL happen, and subtract that fraction from 1. Ex:  Odds of something happening are 4/18.Odds it wont happen are: 1 - 4/18 = 14/18 = 7/9
Term
 Probability - Odds That at Least One Thing Will Happen
Definition
 Use this equation: The probability of what you WANT to happen plus the probability of what you DON'T want to happen equals one.So 1 - the probability that all other outcomes will happen = the probability you're looking for.
Term
 Combinations Ex:  3 categories of menu, different possible selections in each category.  How many different combinations (meals) can you oder?
Definition
 Simple Multiply the number of choices for each of the categories.
Term
 Permutations - Single Source, Order Matters Choosing from a group of similar items with one slight wrinkle.  Or choosing from same source to fill spots.
Definition
 Multiply the number of choices for each of the spots, remembering the number of choices keep getting smaller. Ex:  3 teams, 3 Standings3 x 2 x 1 = 6
Term
 Permutations - Single Source, Order Matters But Only for a Selection
Definition
 Multiply the combinations for each slot, also remembering that the number of choices decreases each time. n = total number of objectsr = number of permutations (slots) n (n - 1)(n - 2)...x(n - r + 1) or n! / (n-r)!
Term
 Combinations: Single Source, Order Doesn't Matter 6 Horses(n)...How many different groups of horses can make up the top 3(r)
Definition
 First find the number of permutations based on what is asked.  Then divide by the permutation of the number of choices/slots (r) n(n-1)(n-2)...x(n-r+1) / r!
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