Math, asked by sank258otge54, 1 year ago

The sum of even numbers between 1 and 31 is

Answers

Answered by Amisha2002
3
REQUIRED SUM=(2+4+6+8+........+30)
(2+4+6+8+.............+2n)=n(n+1)
here, 2n=30
n=30/2=15
15(15+1)=15*16=240 hope this helps !

sank258otge54: thanks pretty
Amisha2002: Ohh NP. Gentlemen!
sank258otge54: what u do for living
sank258otge54: The sum of even numbers between 1 and 31 is
sank258otge54: The sum of odd numbers between 15 and 91 is i want answer for this with formula
Amisha2002: we have a formula to calculate the sum ,
S₁₅ = n/2 [ a + l ]
sank258otge54: thanks again pretty
Amisha2002: :)
sank258otge54: how to calculate sum of odd numbers between 15 and 92
Answered by Anonymous
0
Hi friend !

The first set of even nos: between 1 and 31 are :-
2 , 4 , 6 , .............. and the last one is 30
2 , 4 , 6 ....... 30

here ,
first term = a = 2
common difference = d = 2
last term = l = 30

no: of even no:s between 1 and 31 = n

we know that ,

l = a + [ n - 1 ] d
30 = 2 + [ n - 1 ] 2
30 - 2 = ( n - 1) 2
28 /2 = n - 1
14 = n - 1
n = 15

we have a formula to calculate the sum ,
S₁₅ = n/2 [ a + l ]
= 15/2 x [ 2 + 30 ]
= 15/2 x 32
= 240

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Sum of even no:s between 1 and 31 is 240
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