GRE Math To Memorize Flashcards
The Three Special Products
Special Product #1 = x² - y² = (x+y)(x-y)
Special Product #2 = x² + 2xy + y² = (x+y)(x+y) = (x-y)²
Special Product #3 = x² - 2xy + y² = (x-y)(x-y) = (x-y)²
X percent
X/100
Of
Multiple (usually)
Of z
Z is the Whole (Percents)
Y is X percent of Z
Y is the Part, and Z is the Whole
Y= (X/100)Z
Part = (Percent/100) x Whole
Y is X percent of Z
Y/Z = X/100
Part/Whole = Percent/100
A is 1/6 of B
A=(1/6)B
C is 20% of D
C=(0.20)D
E is 10% greater than F
E=(1+10/100)F = (1.1)F
G is 30% less than H
G = (1-30/100)H = (0.70)H
The dress cost $J. Then it was marked up 25% and sold. What is the profit?
Part = Revenue-Cost Profit = (1.25)J-J Profit = (0.25)J
Ratio of X to Y
X/Y
Common Square Roots
√0 = 0 √1 = 1 √4 = 2 √9 = 3 √16 = 4 √25 = 5 √36 = 6 √49 = 7 √64 = 8 √81 = 9
Common Cubed Roots
3^√0 = 0 3^√1 = 1 3^√8 = 2 3^√27 = 3 3^√64 = 4 3^√125 = 5 3^√216 = 6 3^√343 = 7 3^√512 = 8 3^√729 = 9 3^√1000 = 10
Pythagorean Theorem
a² + b² = c²
- Watch out for the triples!
Diagonal of a square/Face of a cube
d = s√2
Edge of a cube/Diagonal of a cube
d = s√3
Circumference
C = 2πr
Diameter
D = 2r
Area of a Circle
A = πr²
The length of a diagonal across opposite ends of a rectangular solid
D² = l² x w² x h²
Powers of 2
2, 4, 8, 16, 32, 64, 128
Powers of 3
3, 9, 27, 81
Common Numbers²
4² = 16 5² = 25 6² = 36 7² = 49 8² = 64 9² = 81 10² = 100 11² = 121 12² = 144 13² = 169 14² = 196 15² = 225
Common Numbers^3
2^3 = 8 3^3 = 27 4^3 = 64 5^3 = 125
Gross Profit
Gross Profit = Sales revenue - Costs
Ex: May fruit sales = $2,500 and the average wholesale cost per pound of fruit was $0.25 and the average retail price per pound of fruit was $0.80.
1) Average gross profit per pound of fruit solid in May =
0.80 - 0.25 = 0.55
2) Gross profit on fruit sold in May = profit per pound x number of pounds of fruit sold
3) Number of pounds of fruit sold in May = total fruit revenue / revenue per pound
2500 / 0.80 = 3,125 pounds of fruit sold in May
4) Gross profit on fruit sold in May = Profit per pounds (0.55) x number of pounds of fruit sold (3,125)
5) Gross profit = $1,718.75
50 million
5 x 10^7