__ __

**SSC CGL new vacancy 2020 **has** **Quantitative Aptitude paper in tier I and Tier II examination.

__SSC Preparation: Number System__

Whole Number: 0, 1, 2…n

Natural Number: 1, 2...n

Integers: -n… -2, -1, 0, 1, 2...n

Rational Numbers: if p and q are two integers and q≠0, then number in form of p/q is called rational number. Example: 3/2

Irrational Number: This cannot be written in form of p/q. Example: e

Real Number: This exists on number line. It includes all rational and irrational numbers. Example: 0, 1.

Imaginary Number: Real numbers with imaginary number i. Example: 6i

Complex Number: Numbers represented in form of a + bi, where, bi is the imaginary part.

Prime Numbers: These are divided by only 1 or itself.

Example: 3

Note: 1 is not a prime number.

Relative Prime: This does not share any common factor other than 1. Example: 2 and 13

Even Number: These are divisible by 2. Example: 10

Odd Number: These are not divisible by 2. Example: 7

__SSC Preparation: Mensuration__

This technique is used to calculate area, perimeter and volume of different structures.

Formulas

1. Triangle: If a, b and c are three different sides of a triangle, then

Area= √s(s-a) (s-b) (s-c) where s= (a + b + c)/2

Perimeter= a + b + c

· If height and base of a triangle is given, then

Area=*bh

· For equilateral triangle

Perimeter =3a

Area= a^{2}

· For right angle triangle

Area=* base*height

Pythagoras theorem to calculate third side i.e. hypotenuse

h^{2}=p^{2}+b^{2}, where p is perpendicular or height

2. Rectangle:

Area= Length *breadth

Perimeter= 2* (length + breadth)

Diagonal of rectangle =√ (length) ^{2}+ (breadth) ^{2}

3. Square: All sides are equal.

Area= (side) ^{2}

Perimeter= 4 * side

Diagonal= √2 * side

4. Rhombus: All sides are equal but diagonals are different.

Area= *d_{1}*d_{2}

Perimeter= 4* side

5. Circle:

Area= π (radius) ^{2 }where radius= diameter/2

Circumference= 2π* radius

Perimeter of semicircle= π (radius) ^{2}/2

6. Cube: where all three sides are equal.

Volume= (side) ^{3}

Surface Area= 6* (side) ^{2}

Diagonal=√3 *side

7. Sphere: it is in form of solid ball with radius r.

Volume= π (radius) ^{2}

Surface Area= 4 π (radius) ^{2}

__ __

__SSC Preparation: Data Interpretation__

Tips:

· Read and understand question carefully.

· Analyze and sort the data first

· Remember all the basic formulas like average, percentage, ratio, mean etc.

· Fast calculation is the key.

· Pay attention to units of data.

· Approximate value where needed.

__SSC Preparation: Time and work__

More work can be done in same time if we deploy more people.

· If X do a piece of work in N days, then X’s 1 day work is= 1/N

· Part of work completed by X in T days= T/N

· If X is N times as good in work as Y, then:

Ratio of work done by A and B = N: 1

Ratio of times taken by A and B to finish a work = 1: N

· X and Y can do a piece of work in‘a days and‘b’days respectively, then working together:

Time to complete the work = (a b)/ (a + b)

In one day, they will finish= (a + b)/ (a b)

__ __

n By: Swati Mishra