Reading...
Play button
Play button
Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
38 Cards in this Set
- Front
- Back
|
Steps to solving Age problems?
|
Make an age chart. It helps assign variables you can use to write equations.
|
|
|
What is the GMAT's favorite Word Translation problem?
|
Rate problems. The most common rate problem is the work problem.
|
|
|
Rate problems come in five forms:
|
Basic Motion, Average Rate, Simultaneous motion, Work, and Population.
|
|
|
How do you solve an average rate problem? Lucy walks to work at a rate of 4 mi/hr, and walks home at 6 mi/hr. What is Lucy's average walking rate round trip?
|
To find the average rate, you must first find the TOTAL combined time for the trips and TOTAL combined distance for the trips. Pick any number for the distance = 12. Figure out 3 hours + 2 hours = 5 total hours for 24 miles. Rate is 24 miles/5 hrs.
|
|
|
More difficult rate problems involve _______
|
More than one rate. Simultaneous Motion.
|
|
|
When two vehicles travel at different rates in opposite directions, eventually meeting somewhere in between….what tactic can you use?
|
Clicking charts
|
|
|
If Train A leaves 10 min after Train B ____________________(assign variables)
|
then Train A's time is t minutes and Train B's time is t+10.
|
|
|
If two people are moving TOWARDS each other, then what happens to the rates?
|
Combined rate…(Rate1 + Rate2) = combined rate….
|
|
|
If two people are moving AWAY from each other, then happens?
|
They travel for the same TIME, but for different DISTANCES. (2 charts, add distances)
|
|
|
If two people are moving along the SAME PATH, then what happens?
|
They travel for different TIIMES, but the same DISTANCE. (make 2 charts = d )
|
|
|
In work problems, distance is replaced by _____
|
work
|
|
|
If two people are working together, then…..
|
add their rates.
|
|
|
The population of a certain bacteria triples every 10 minutes. If the population of a colony 20 minutes ago was 100, in approximately how long from now will the bacteria population reach 24,000?
|
20 min ago - 100. 10 min ago - 300. Now - 900. In 10 min - 2700. In 20 min - 8100. In 30 min - 24,300…just make a chart.
|
|
|
For population problems, often use ______
|
Benchmark values / estimates.
|
|
|
Combinatorics: Different sources _______
|
Just multiply
|
|
|
Larry has 3 shirts, 2 pants, and 3 hats. How many different outfits could he have?
|
3*2*3
|
|
|
If there are 4 people and 4 chairs in a room, how many different seating arrangements?
|
4! Or 4*3*2*1
|
|
|
If there are 7 people in a room, but only 4 chairs available, how many different arrangements are available?
|
7! / 3! (Divide factorial by number of repeated letters). Or 7c4 = 7*6*5*4
|
|
|
If order does not matter, what would the anagram look like?
|
Use Y/N. Or, know combinations and divide by number of choices…
|
|
|
If a team of 4 is chosen from 7 people in a room, how many different teams are possible?
|
YYYYNNN => (7!)/(3!4!) OR 7 choosing 4 and divide by # ways to arrange => 7*6*5*4 / (4*3*2*1)
|
|
|
6 people go to movies. If two of them will not sit next to each other, in how many different arrangements can the 6 people sit?
|
Total - #ways to sit as couple = ways not sit as couple. Total = 6!. Ways could sit = 2! (ways to arrange the two) * 4! (ways to arrange the other 4) * 5 (seating pairs)…6! - (2! * 4! * 5)
|
|
|
Convert all probability problems to ______ instead of percents, decimals,
|
fractions
|
|
|
Probability that x AND y will happen?
|
MULTIPLY probabilities
|
|
|
Probability that x OR y will happen?
|
ADD probabilities
|
|
|
Find the probability that something will not happen => what rule?
|
1-x. Pwill + Pwon't = 1
|
|
|
Renee has a bag of candy. Bag has 1 candy bar, 2 lollipops, 3 jellybeans, and 4 truffles. Jack takes one piece of candy out of the bag at random. If he picks a jellybean, he chooses one additional piece of candy and then stops. If he picks any non jelly bean candy, he stops picking immeidately. After Jack picks his candy, Renee will pick a piece of candy. What is the probability tha Renee picks a jellybean?
|
List all winning scenarios. JB, notJB, JB. JB, JB, JB. Not JB, ____, JB. Then find individual probabilities and MULTIPLY b/c AND. Then you have 3 scenarios for Renee to get 1 jellybean. 3/10 is the answer.
|
|
|
Kate and Amy want to be on the same team. 6 girls in the group, and only 4 of them will be placed on the team. What is the probabilty that Kate and Amy will both be on the team?
|
Total number of 4 person teams / Total number of teams that include Kate and Amy. # of different 4 person teams => 6c4 or 6! / 2!*4! => 15 possible groups. Total number of 4 person teams include all the winning scenarios in which Kate, Amy, and 2 other people get on the team. 4c2 or 4! / 2!*2!. => 6 winning scenarios.
|
|
|
Average =
|
Total / number of terms
|
|
|
Sam earned $2,000 commission on a big sale, raising his average commission by $100. If Sam's new average commission is $900, how many sales has he made?
|
Make two average pies: Before the sale and after the sale. Before the sale => 800n = Total or Sum. After the sale => 800n + 2000 / (n+1) = 900. If n=11, then total sales = 12.
|
|
|
For any set in which terms are spaced evenly apart, the average =>
|
Middle Number
|
|
|
For any evenly spaced set of numbers {101, 111, 121…581, 591, 601} find the middle number?
|
Add first and last terms and divide that sum by 2. 101 + 601 / 2 => 351. (Only works for evernly spaced set of numbers)
|
|
|
Given ascending set x,x,y,y,y,y, what is greater, the median or the mean?
|
Median is larger b/c median is y, and the mean is x + y / 2 which is less than y.
|
|
|
What does standard deviation measure?
|
How far data points in distribution fall from the mean. 34:14:2
|
|
|
If data points in a set are close to the mean, then there is a _____SD
|
small standard deviation
|
|
|
Translation problems that involve 2 or more given sets of data that partially intersect are called_______
|
Overlapping sets
|
|
|
What can you use to visualize the categories of overlapping sets?
|
Use A, Not A and B, Not B and Totals… OR G1 + G2 - Both + Neither = Total
|
|
|
Overlapping sets involving percents - what is your strategy?
|
Use 100 Smart Number to represent Total!
|
|
|
Problems involving 3 overlapping sets can be solved by using a
|
Venn Diagram - work from the inside out…
|
