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GRE: Math3

GRE Math3 Flashcards - Most Studied - #7,9,10,12 I deleted ones that didn't make sense
Kalvin
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  • Distance
    (rate)(time) d=rt
  • Rate
    d/t (distance)/(time)
  • Time
    (distance)/(rate) d/r
  • How do you solve proportions? a/b=c/d
    Cross multiplication a/b=c/d 4/6=10/15 4(15)=6(10) 60=60
  • If a lamp increases from $80 to $100, what is the percent increase?
    = 25%. = (actual increase/original amount) x 100% = 20/80 x 100% = 1/4 x 100% = 25%
  • The percent decrease of a quantity
    = (actual decrease/Original amount) x 100%
  • If a lamp decreases to $80, from $100, what is the decrease in price?
    = (actual decrease/Original amount) x100% = 20/100x100% = 20%
  • To increase a number by x%
    multiply by 1+x% i.e. 100 x (1+50%)=100x1.5=150
  • To decrease a number by x%
    multiply by 1-x% i.e. 100 x (1-50%)=100x.5=50
  • THE DENOMINATOR CAN NEVER
    BE ZERO! 1/∅=null
  • If a>b then
    -a<-b
  • The reciprocal of any non-zero number is
    1/x
  • Probability of an Event
    P(E) = number of favorable outcomes/total number of possible outcomes
  • If Event is impossible
    P(E) = ø
  • If E is certain
    P(E) = 1/1 = 1
  • Probability of Event all cases
    ∅≤P(E)≤1
  • Probability of E not occurring
    1 - P(E)
  • Circumference of a circle
    pi(diameter)
  • Circumference of a circle
    2(pi)r
  • Area of a circle
    (pi)r²
  • Volume of a rectangular solid
    (length)(width)(height)
  • Volume of a cube
    edge³
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GRE