All flashcard decksSSC CGL syllabus →
30 cardsSSC CGL

Quantitative Aptitude and Reasoning: Key Formulas

Thirty cards with the arithmetic, geometry, calendar and ranking formulas that students use most often in the SSC CGL.

Start studyingPlay Match
PDF study sheet

Free account needed to save, copy or download. We bring you back here.

1 / 30
0 known
TermClick or press Space to flip
Profit % formula
GetMyMockTestQuestion side

Full list

Terms in this deck (30)

SSC CGL mock tests →
1
Profit % formula
Profit % = (profit / cost price) x 100; loss % uses the loss in place of profit.
2
Selling price from profit %
SP = CP x (100 + profit%) / 100.
3
Successive discounts of a% and b%
Net discount % = a + b - ab/100.
4
Simple interest
SI = PRT / 100.
5
Compound amount
A = P(1 + R/100)^T.
6
CI - SI for 2 years
P(R/100)^2.
7
Time and work
If A takes a days and B takes b days, together they take ab/(a + b) days.
8
Pipes and cisterns
Filling pipes add their rates; an emptying pipe subtracts.
9
Speed, distance, time
Distance = speed x time; km/h to m/s: multiply by 5/18.
10
Average speed for equal distances
2xy/(x + y) for speeds x and y.
11
Trains crossing a pole or a platform
Pole: time = length / speed. Platform: time = (train + platform) / speed.
12
Trains in opposite directions
Relative speed = sum of the speeds.
13
Boats and streams
Downstream = u + v; upstream = u - v; still water speed = (down + up)/2.
14
Alligation
Ratio = (dearer - mean) : (mean - cheaper).
15
Average
Sum of the observations divided by their number.
16
HCF x LCM
HCF x LCM = product of the two numbers.
17
Area of a triangle (Heron)
√(s(s - a)(s - b)(s - c)) with s = (a + b + c)/2.
18
Volume of a cylinder, cone and sphere
pi r² h; (1/3) pi r² h; (4/3) pi r³.
19
Surface area of a sphere
4 pi r².
20
Pythagoras
Hypotenuse² = base² + height².
21
Trigonometric values
sin 30 = 1/2, sin 45 = 1/√2, sin 60 = √3/2; tan 45 = 1.
22
Sum of the first n natural numbers
n(n + 1)/2.
23
Sum of the first n odd numbers
n².
24
Percentage change
(new - old) / old x 100.
25
Ratio and proportion
If a : b = c : d then ad = bc.
26
Algebraic identity
(a + b)² = a² + 2ab + b²; a² - b² = (a + b)(a - b).
27
Calendar odd days
100 years = 5 odd days, 200 = 3, 300 = 1, 400 = 0; each leap year adds 2.
28
Angle between clock hands
|30h - 5.5m| degrees.
29
Rank from the other end
Total - rank + 1.
30
Letter position from the right
27 minus the position from the left.

More SSC CGL practice

SSC CGL mock tests

All SSC CGL practice →