Prime Numbers
List all the prime numbers less than 22
9. Work Problems
What is the formula to use for work problems?
If Sue can do a job in 3 hours and Bob can do the same job in 6 hours, how long will it take them working together at their respective rates?
If Tom can do a job in 10 hours and Tom and Mary together can do the job in 6 hours working at their respective rates, how long will it take Mary to do the job by herself?
10. Percent Problems
What number should you always pick for percent problems?
What formula will give you the percent increase/decrease?
What formula will give you what percent the new quantity is of the old quantity?
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Prime Numbers
ReplyDeleteList all the prime numbers less than 22
2 (1 is not a prime number!), 3, 5, 7, 11, 13, 17, 19
Work Problems
What is the formula to use for work problems?
(X*Y)/(X+Y) = Combined time of two workers (C) where X equals the time of one worker working alone and Y equals the time of the other worker working alone
If Sue can do a job in 3 hours and Bob can do the same job in 6 hours, how long will it take them working together at their respective rates?
2 hours
If Tom can do a job in 10 hours and Tom and Mary together can do the job in 6 hours working at their respective rates, how long will it take Mary to do the job by herself?
10Y/(10 + Y) = 6 so Y = 15 hours
Percent Problems
What number should you always pick for percent problems?
100
What formula will give you the percent increase/decrease?
[(New # - Old #)/Old #] * 100
What formula will give you what percent the new quantity is of the old quantity?
(New #/Old #) * 100