**Time**

**Introduction :**

Time is an entity which is used to calculate the duration i.e.(in hours, minutes and second). This is also used in terms of months and years while calculating the interest rates(simple and compound interest), and it is used in many forms to mainly to calculate duration.

Time is usually specified using the terms such as hours, minutes and seconds, which plays an important role in calculating time. Time is represented generally as

HH:MM:SS

(06:24:12) 6hours 24 minutes 12 seconds

Where: H = hours, M = minutes, S = seconds

Relation between hour, minute and second is:

1hour = 60minutes

1minute = 60seconds

**Time in calculating distance, speed, rate**

**Formulas: **Distance = Rate x Time

Rate=Distance/Time

Time=Distance/Rate

Time = Distance / Speed

Distance = Time x Speed

Speed = Distance / Time

Acceleration=(vf-vi)/t

Where, vf and vi are initial and final velocities and t is the time.

**Money**

**Introduction**

Counting moneyis a simple technique which involves all the basic mathematics techniques such as addition, subtraction, division and multiplication.Money countingcan be made in different forms which can be done bycounting coins, counting dollars, counting bills etc. And in special cases such as lending money in these cases the money can be counted using some techniques like rate and interest etc.

**Counting bills using money**

The money can also be calculated using bills in this technique we need to pay the extra amount including original amount the extra amount is known as tax. Tax will be represented in the form of percentage.

**Counting money using interest rates **

Interest is a fee paid on borrowed assets. It is the price paid for the use of borrowed money. The interest is calculated upon the value of the assets in the same manner as upon money. The percentage of the principal that is paid as a fee over a certain period of time is called the interest rate.

There are two types of interest rates such as simple and compound interest.

**Simple interest:**

Simple interest is the rate of interest which is calculated upon the original principle amount, it is usually used for the short terms and it is calculated using the formula

SI = P x I x N

Where: P – Principle amount,I – Interest rate for one , N – Number of periods.

**Compound interest:**

Compound interest is paid on the original principal and on the accumulated past interest, and it is calculated using the formula

A = P (1 + r)^{n}

Where:

P is the principal (the initial amount you borrow or deposit)

r is the annual rate of interest (percentage)

n is the number of years the amount is deposited or borrowed for.

A is the amount of money accumulated after n years, including interest.

## Graphs

**Introduction**

Graphing is the technical which is used for plotting the points in theco-ordinate system.This technic is used for geometric construction like (line,curve etc.),and these are also used to find the growth of a system.

**Properties:**

?To plot the point in co-ordinate system.

?Graphing is done by 2d mostly(x,y axis),and some times in 3d.

?Negative graphing is also a graphing technic which shows the downfall of a particular system.

?Logarithmic values are plotted in graphs.

**Types**

1.Line graphs

2.Pie charts

3.Bar graphs

**Line graph:**

A line graph is used to summarize a particular information ,depending upon the various parameters.The line goes based on the co-ordinates (x,y) along the x and y axis.

**Pie chart:**

Pie chartis represented in a circle. Therefore its also known as "circle graph".The circle is divided into different partition depending on values.

**Bar graph:**

A bar graph consist two axes and a series of horizontal bars or vertical bars are placed in the x ,y plane,depending on the value.

## Solved Examples :

1) Calculate the simple interest for the amount of $1000 and the annual interest rate is 4% for 4 years.

Solution :

P = 1000,I = 4%, N = 4 years.

Simple interest = P x I x N

= 1000 x 4% x 4

= 1000 x 4/100 x 4

= 10 x 4 x 4

= 10 x 16

= 160

The simple interest is $160.

2)Plot the graph for the given expression y=x+3?

Solution :

Expression:y=x+3

In the above graph each point is plotted on the line by the expression y=x+3.

3)When a boy started from point A and travel led 25km at the rate of 5kmph,Calculate the time?

Solution :

distance=25km, rate=5kmph

We know that,time=distance /rate

=25/5

time required is 5hours.