LS EM

Question 1

y is directly proportional to x

Answer 1

y/x=k or y=kx
Where k is a constant

Question 2

y is inversely proportional to x

Answer 2

xy=k or y=k/x
Where k is a constant

Question 3

Probability of event A

Answer 3

P(A) = number of outcomes favourable to A/total number of equally likely outcomes

Question 4

Sample space

Answer 4

S={ }

Question 5

+- constant diff

Answer 5

nth term = a+(n-1)d
a –> first term
d –> constant diff

Question 6

Combination formula

Answer 6

An=Bn+Cn+Dn
An –> whole sequence
Bn –> 1st type
Cn –> 2nd type
Dn –> 3rd type

Question 7

× constant diff

Answer 7

nth term = ar^(n-1)
a –> 1st term
r –> constant diff being ×

Question 8

+- varying diff

Answer 8

nth term = a+(n-1)d, +1/2(n-1)(n-2)d
a –> 1st term
d –> 1st diff
d –> constant diff btw diff

Question 9

Speed

Answer 9

D
S T

Question 10

TSA of a cube

Answer 10

6a^2

Question 11

Vol of cube

Answer 11

a^3

Question 12

TSA of cuboid

Answer 12

2lh+2hb+2lb

Question 13

Vol of cuboid

Answer 13

lbh

Question 14

Curved SA of cylinder

Answer 14

2πrh

Question 15

TSA of cylinder

Answer 15

2πrh+2πr^2

Question 16

Vol of cylinder

Answer 16

πr^2h

Question 17

Vol of prism

Answer 17

area of cross-section × L

Question 18

Vol of pyramid

Answer 18

1/3×BA×h

Question 19

CSA of cone

Answer 19

πrl

Question 20

TSA of cone

Answer 20

πrl+πr^2

Question 21

Vol of cone

Answer 21

1/3πr^2h

Question 22

TSA of sphere

Answer 22

4πr^2

Question 23

Vol of sphere

Answer 23

4/3πr^3

Question 24

TSA of 1/2 sphere

Answer 24

3πr^2

Question 25

Vol of 1/2 sphere

Answer 25

2/3πr^3

Question 26

mm^2-->cm^2-->m^2-->km^2

Answer 26

÷100 ÷10 000 ÷1 000 000

Question 27

mm^3-->cm^3-->m^3-->km^3

Answer 27

÷1 000 ÷1 000 000

Question 28

A and P of rectangle

Answer 28

A = a×b P=2(a+b)

Question 29

A and P of square

Answer 29

A=x^2 P=4x

Question 30

A&P of triangle

Answer 30

A=1/2×b×h P=a+b+c

Question 31

A&P of parallelogram

Answer 31

A=b×h P=2(a+b)

Question 32

A&P of trapezium

Answer 32

A=1/2(a+b)h P=a+b+c+d

Question 33

A&P of circle

Answer 33

A=πr^2 P=2πr/πd

Question 34

A&P of sector

Answer 34

A=θ/360°×πr^2 P=θ/360°×2πr+2r

Question 35

A&P of semi-circle

Answer 35

A=1/2πr^2 P=πr+2r or 1/2πd+d

Question 36

Sum of int. angles

Answer 36

(n-2)×180°

Question 37

Sum of ext. angles

Answer 37

360°