Formulas

Question 1

No of factors of a no expressed as 2ᵃ.3ᵇ.5ᶜ.7ᵈ… (a, b, c, d… >= 1)

Answer 1

Total=> (a+1)(b+1)(c+1)(d+1)…; Odd=> (b+1)(c+1)(d+1)…; Even=> total - odd

Question 2

(n+1)²

Answer 2

n² + n + (n+1)

Question 3

Work Questions

Answer 3

A=RT; combined work rate of people/machines working together = SUM of individual work rates

Question 4

Set of items with identical items [No of distinct arrangements]

Answer 4

n! / (b! c! d!)

Question 5

Average velocity

Answer 5

Total distance / Total time

Question 6

Relationship: LCM & HCF of M & N

Answer 6

LCM x HCF = M x N

Question 7

Simple interest

Answer 7

Principal x Rate x Time

Question 8

nth term of a sequence

Answer 8

aₙ = a₁ + (n-1)d

Question 9

Slope b/w 2 points

Answer 9

rise/run (y₂-y₁ / x₂-x₁)

Question 10

% change

Answer 10

[(New - Orig)/Orig] x 100

Question 11

Range

Answer 11

Max - Min

Question 12

Equation of a Line (given slope & 1 point)

Answer 12

y-y₁ = m (x-x₁)

Question 13

Factor of every number

Answer 13

1

Question 14

Distance b/w 2 points

Answer 14

rootof [ (y₂-y₁)² + (x₂-x₁)² ]

Question 15

% (part, whole)

Answer 15

(part/whole) x 100

Question 16

Parabola (vertex)

Answer 16

y=ax²+bx+c; x = -b/2a

Question 17

Average of whole (A1 - p1, A2 - p2, A3 - p3)

Answer 17

A1p1+A2p2+A3p3

Question 18

Sum of integers b/w two numbers

Answer 18

no of integers / 2 [first no + last no]; number of integers x to y inclusive = y-x+1

Question 19

Compound interest (total amount)

Answer 19

p(1+r/n)^nt

Question 20

Binomial Formula

Answer 20

nCr * p^r [ (1-p)^(n-r) ]

Question 21

P(atleast 1 occurence of A)

Answer 21

1 - P(No occurence of A)

Question 22

Sum of all factors of a prime no (X)

Answer 22

1 + X

Question 23

General Events - P(A and B)

Answer 23

P(A)P(B/A) (or) P(B)P(A/B)

Question 24

General Events - P(A or B)

Answer 24

P(A) + P(B) - P(A and B)

Question 25

Independent Events - P(A and B)

Answer 25

P(A) x P(B)

Question 26

Independent Events - P(A or B)

Answer 26

P(A) + P(B) - [ P(A) x P(B) ]

Question 27

Mutually Exclusive Events - P(A and B)

Answer 27

0

Question 28

Mutually Exclusive Events - P(A or B)

Answer 28

P(A) + P(B)

Question 29

Order doesn’t matter & repetition is allowed

Answer 29

(r + n - 1)! / r! (n - 1)!

Question 30

Order doesn’t matter & repetition is NOT allowed

Answer 30

n! / r! (n - r)!

Question 31

Order matters & repetition is allowed

Answer 31

n^r

Question 32

Order matters & repetition is NOT allowed

Answer 32

n! / (n - r)!

Question 33

X/Y=?

Answer 33

Q+(R/Y)

Question 34

X/Y=?

Answer 34

Q+(R/Y)