**Simple Interest:**

· Let Principle = P, Rate = R% per annum (p.a.) and Time = T years. Then,

**(i)** S.I. = PRT/100

**Compound Interest:**

· Let Principal = P, Rate = R% per annum, Time = n years.

**(I) **When interest is compound Annually: Total amount = P ( 1 + R/100)^{n}

**(II) **When interest is compounded Half-yearly: Total amount = P( 1 + R/200)^{2n}

**(III) **When interest is compounded annually but time is in fraction, say 3 2/5 years.

**(IV) **When Rates are different for different years, say R_{1} %, R_{2}%, R_{3} % for 1^{st}, 2^{nd}, and 3^{rd} year respectively.

Then, Amount = P ( 1 + R_{1}/100)(1 + R_{2}/100)(1+ R_{3}/100)

**CI - SI (for 2 years) = PR ^{2}/100x100**

**Sales Tax**

**Calculation of Sales Tax**

· The price marked on an article is called its **marked price** or list price.

· The price at which an article is offered to the customer is called its **sale price**.

· The sales tax is always calculated on the sale price of the article.

**(i) **When no discount is given, marked price of the article becomes the sale price, and sales tax is calculated on it.

**(ii) **When discount is given, we first calculate the sale price as under:

Sale Price = (Marked Price) – (Discount)

**Shares:**

· **Capital:** The total amount of money needed to run the company is called the capital.

**Shares**: The whole capital is divided into small units, called shares.

**Dividend:** The annual profit distributed among share holders is called dividend.

**Nominal Value of a Share (N.V.):**

· The value of a share printed on the share certificate is called its Nominal Value or Face Value or Par Value.

· Dividend is always reckoned on the face value of a share.

**Market Value of a Share (M.V.):**

· The shares of different companies can be bought or sold in the market through stock-exchange.

· The price at which the share is sold or purchased in the market through stock exchange is called its Market Value.

**A share is said to be: **

·**(i) At premium or above par, **if its market value is more than its face-value.

**(ii) ****At par**, if its market value is the same as its face value.

**(iii) ****At Discount or below par**, if its market value is less than its face-value.

**Examples:**

**(i) **If Rs 100 share is quoted at a premium of Rs 24, then

Market Value of 1 share = Rs (100 + 24) = Rs 124.

**(ii) **If Rs 25 share is quoted at a discount of Rs 7, then

Market Value of 1 share = Rs (25 – 7) = Rs 18.

**Some Important Concepts:**

**(i) **The face value of a share always remains the same.

**(ii) **The market value of a share changes from time to time.

**(iii) **Dividend is always paid on the facee value of a share.

**(iv) **Number of shares held by a person

**Example: ****9% Rs 100 share at Rs 120 means:**

**(i) **Face Value (N.V.) of 1 share = Rs 100.

**(ii) **Market Value (M.V.) of 1 share = Rs 120.

**(iii) **Annual Dividend on 1 share = 9% of its Face Value = 9% of Rs 100 = Rs 9.

**(iv) **An investment of Rs 120 gives an annual income of Rs 9.

**(v) **Rate of return p.a. = Annual income from an investment of Rs 100