Question

Find the sum of all odd numbers from 351 to 373

Answer 1

Answer:

4344

Step-by-step explanation:

a=351    d=2

n=x      tn=373

tn=a+(n-1)d

373=351+2n-2

12=2n

n=6

sn=n/2(a+tn)

sn=6*724

sn=4344

Answer 2

Given:-

• An A.P 351, 353, 355, . . . . . , 373

To Find:-

• Sum of the A.P

Formula used:-

• $a_n= a+(n-1)d$

• $S_n=\dfrac{n}{2}(a+l)$

Solution:-

Here,

• a = 351

• d = 353 - 351 = 2

• $a_n\:or\:l\:= 373$

Now,

$\implies\:a_n= a+(n-1)d$

$\implies\:373= 351+(n-1)2$

$\implies\:373= 351+2n-2$

$\implies\:373-349= 2n$

$\implies\:2n=24$

$\implies\:n=\dfrac{24}{2}$

$\implies\:n=12$

Now using,

$S_n=\dfrac{n}{2}(a+l)$

$\implies\:S_n=\dfrac{12}{2}(351+373)$

$\implies\:S_n=6×724$

$\implies\:S_n=4344$

Hence, The sum of all odd numbers from 351 to 373 is 4344.

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More Formulas:-

• $S_n=\dfrac{n}{2}[2a+(n-1)d]$

• $S_n=\dfrac{n}{2}[a+a+(n-1)d]$

• $S_n=\dfrac{n}{2}(a+a_n)$

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