• Ratio: Comparing by division is called ratio.
    • Quantities written in ratio have the same unit.
    • Ratio has no unit.
  • Proportion: Equality of two ratios is called Proportion.
  • Product of extremes = Product of means
  • Percentage: Percentage means for every hundred. The result of any division in which the divisor is 100 is a percentage. The divisor is denoted by a special symbol %, read as percent.

Profit and Loss

  • Cost Price (CP): The amount for which an article is bought.
  • Selling Price (SP): The amount for which an article is sold.
  • Overhead expenses are additional expenses made after buying an article are included in the cost price.
  • Discount is a relaxation offered on marked price. Discount = Marked Price – Sale Price.
  • Discount can be calculated when discount percentage is given. Discount = Discount % of Marked Price
  • CP = Cost price + overhead expenses.
  • Sales tax is charged on the sale of an item by the government and is added to the Bill Amount. Sales tax = Tax% of Bill Amount
  • Simple Interest: If the principal remains the same for the entire loan period, then the interest paid is called simple interest.
    • SI = (P X R X T)/1000
  • Compound Interest is the interest calculated on the previous year’s amount (A= P+I)
    • Amount when interest is compounded annually = P(1 + R/100)n; P is principal, R is rate of interest, n is time period.
    • Amount when interest is compounded half yearly = P(1 + R/100)2n; R/2 is half yearly rate and 2n = number of ‘half-years’

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