Quantitative Aptitude Topics

Alligation or Mixture

1. Alligation: It is the rule that enables us to find the ratio in which two or more ingredients at
the given price must be mixed to produce a mixture at a given price.
2. Mean Price: The cost price of a quantity of the mixture is called the mean price.
3. Rule of Alligation: If two ingredients are mixed, then:
We represent the above formula as below

(Cheaper quantity) : (Dearer quantity) = (d – m) : (m – c)

Also Read ► Important Banking Gk for SBI PO 2014 Exam

Simple Interest

1. Let Principle = P, Rate = R% per annum and Time = T years. Then,
a. S.I. = ( P × R × T ) / 100
b. P = ( 100 × S.I. ) / ( R × T ),
c. R = ( 100 × S.I. ) / ( P × T ),
d. T = ( 100 × S.I. ) / ( P × R ).


Compound Interest

1. Let Principle = P, Rate = R% per annum and Time = T years. Then,
I. When interest is compounded Annually,
Amount = P (1 + R/100)N
II. When interest is compounded Half-yearly:
Amount = P (1 + R/2/100)2N
III. When interest is compounded Quarterly:
Amount = P (1 + R/4/100)4N
2. When interest is compounded Annually, but the time is in fraction, say 3⅞ years.
Then, Amount = P (1 + R/100)3 × (1 + ⅞R/100)
3. When Rates are different for different years, say R1%, R2%, R3% for 1st, 2nd, and 3rd year
respectively,
Then, Amount = P (1 + R1/100) (1 + R2/100) (1 + R3/100)
4. Present worth of Rs. x due n years hence is given by:
Present Worth = x / (1 + R/100)n