# CSAT

## QUANTITATIVE  APTITUDE

### Numbers

A number is divisible by 2, if its unit’s place digit is 0, 2, 4, or 82.
A number is divisible by 3, if the sum of its digits is divisible by 33.
A number is divisible by 4, if the number formed by its last two digits is divisible by 44.
A number is divisible by 8, if the number formed by its last three digits is divisible by 85.
A number is divisible by 9, if the sum of its digits is divisible by 96.
A number is divisible by 11, if, starting from the RHS,(Sum of its digits at the odd place) – (Sum of its digits at even place) is equal to 0 or 11x7.
Results on Division:Dividend = Quotient × Divisor + Remainder
An Arithmetic Progression (A. P.) with first term ‘a’ and Common Difference ‘d’ is givenby:[a], [(a + d)], [(a + 2d)], … … …, [a + (n – 1)d] nth term, Tn = a + (n 1)d Sum of first ‘n’ terms, Sn= n/2 (First Term + Last Term)16.
A Geometric Progression (G. P.) with first term ‘a’ and Common Ratio ‘r’ is given by:a, ar, ar

### Simplification

BODMAS Rule

1] Bracket  2] Order  3] Division  4] Multiplication  5] Addition  6] Subtraction

### Pipes and Cistern

X = Pipe fill the tank      (X1, X2, X3 ….etc.)

Y = Pipe empty the tank     (Y1, Y2, Y3 ….etc.)

Time required to fill tank in 1 hr. is = 1/x1 + 1/x2

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