Veto q&a 7 Month22 (1)

n = 30, a= 40, d= 20
30
S
n
= 80 29 20
2
= 15 [80+29+20]
=15 [80+580]
= 15 x 660
= 9900
[ + × ]
aVeRaGe
• Average =
Sum of observations
number of observations
n + 1
• Average of first ‘n’ Natural Numbers =
2
• Average of first ‘n’ Odd Numbers = n
• Average of first ‘n’ Even Numbers = n + 1
Sum of fiRST ‘n’ numBeRS
n( n+ 1)
• Sum of first ‘n’ Natural Numbers =
• Sum of the squares of first ‘n’ Natural Numbers
n n
=
@hang out
( + 1)( 2n+
1)
• Sum of the cubes of first ‘n’ Natural Numbers
2
⎡ n( n+ 1)
⎤
= ⎢ ⎥
⎣ 2 ⎦
• Sum of the first ‘n’ Whole Numbers =
n n−
1
• Number of shakehands =
2
• Sum of first ‘n’ Odd Numbers = n 2
• Sum of first ‘n’ Even Numbers = n(n+1)
PeRcenTaGe
• If x% of a Number = y,
y
then the Number = ×100
x
6
( )
•
y
y% of x = x × 100
• z% of y% of x =
y z
× ×
100 100
2
• If x% of a Number = y,
y
then its z% = × z
x
RaTio anD PRoPoRTion
•
a
a : b =
b
• If a : b = c : d then
a x d = b x c
• If a, b, c are in proportion then
a : b = b : c
• If xA = yB = zC then
a : B : c = 1 : 1 :
1
x y z
•
1 1 1
: :
x y z = A : B : C then,
x : y : z =
1 1 1
: :
A B C
•
A B C
If = =
x y z
then
a : B : c = x : y : z
2018
May
SimPle anD comPounD inTeReST
PNR
• Simple Interest, I =
100
• Annual Compound Interest
• Half yearly Compound Interest
• Quarterly Compound Interest =
• The difference between Compound and Simple
Interest for 2 years for a particular amount ‘P’
⎛ R ⎞
= P ⎜ ⎟
⎝100
⎠
2
PRofiT anD loSS
• Gain = Selling Price - Cost Price
N
⎛100
+ R ⎞
= P⎜
⎟ − P
⎝ 100 ⎠
2N
⎛ R ⎞
⎜100
+ ⎟
= P 2
⎜ ⎟ − P
⎜ 100 ⎟
⎝ ⎠
4N
⎛ R ⎞
⎜100
+ ⎟
P 4
⎜ ⎟ − P
⎜ 100 ⎟
⎝ ⎠
Q&A Bonus
“May all become Happy” was the motto of which University - Kerala university 55