Percent means per every hundred and denoted by the symbol %. A fraction with denominator 100 is called a Percent.

### 1. Profit and Loss

Cost Price (CP): Amount paid to buy an article.

Selling Price (SP): Amount at which an article is sold.

Profit or Gain: When SP > CP, the seller makes a profit or gain.

Gain = SP - CP

Loss: When CP > SP, the seller incurs a loss.

Loss = CP - SP

Gain and loss are always calculated on the CP.

Gain % = (Gain x 100)/CP

Relation between SP and CP: In case of Gain:

Marked price or list price (MP): Price at which a article is listed for sale.

Discount: Reduction in the marked price of an article.

Net selling price (SP): SP = MP - Discount

### 2. Interests

Principal (P): Money borrowed.

Interest (I): Extra or additional money paid by the borrower.

Amount (A): Total money paid by the borrower.

A = P + I or I = A – P

Rate (R): Interest on Rs. 100 for 1 year is known as the rate percent per annum.

Simple Interest (SI): Interest which is calculated uniformly on P throughout the loan period.

SI = (P x R x T)/100

Compound Interest (CI): Interest obtained during the first time period is added to the original P and amount becomes new P for the second time period and so on. The difference between the amount obtained at the last time period and original principal is called compound interest. 