Manav Goyal

Introduction - Aptitude

  • LCM (Least Common Multiple) & HCF (Highest Common Factor)
    • Find LCM & HCF of fractional numbers
      • HCF = HCF of numerators/LCM of denominators
      • LCM = LCM of numerators/HCF of denominators
    • Find LCM & HCF of decimal numbers
      • Make the no. of digits after decimal equal for all numbers
      • Remove decimals
      • Calculate HCF of numbers & Put decimal at the same position to get HCF
      • Calculate LCM of numbers & Put decimal at the same position to get LCM
    • Product of 2 no. = Product of their LCM & HCF
    • Find largest no. which divides these numbers to leave the same remainder
      • Find HCF of difference of these numbers
  • Simplification
    • BODMAS (Bracket Of Division Multiplication Addition Subtraction)
      • Bracket => () {} []
  • Average
    • Avg speed of a return trip = 2 * x * y/x + y
  • Age
  • Surds and Indices
    • Error
    • Question type
      • Sometimes assume some value to "x" and later substitute it back
  • Percentage
    • Increased value => (100 + x) % of N
    • Decreased value => (100 - x) % of N
    • Value after "n" years if increasing at the rate of "r" = N(1 + r/100)n
      • Value before "n" years if increasing at the rate of "r" = N/(1 + r/100)n
    • Value after "n" years if decreasing at the rate of "r" = N(1 - r/100)n
  • Profit & Loss
    • Profit = SP - CP
    • % Loss when x% gain & loses = (x%/10)2
  • Ratio and Proportion
    • a (Antecedent) : b (Consequent)
    • a : b :: c : d
      • a & d are called extremes and b & c are called means
      • a x d = b x c
    • Question type
      • Third proportion => a:b :: b:c
      • Mean proportion = √ab
      • Duplicate ratio => a2 : b2
        • Sub-duplicate ratio => √a : √b
      • Triplicate ratio => a3 : b3
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