Question

find the sum of following
a.p 1/15,1/12,1/10......
to 11 terms
​

Answer 1

Answer:

NO THANKS. .............. ........

Answer 2

Here is your answer dear⛄

➽ Sum of n terms of A. P. =

${S}_{n}$ = $\frac{n}{2}$ [ 2a + (n-1)d ] -------> ①

Where,

• First term = a
• Common difference = d
• Number of terms = n

$\frac{1}{15}$, $\frac{1}{12}$, $\frac{1}{10}$ ...................... to 11 terms

• a = $\frac{ 1 }{ 15 }$
• d = ( $\frac{1}{12}$ ) - ( $\frac{1}{15}$ )
• d = $\frac{ 1 }{ 60 }$

➽ From equation ①

❥ ${S}_{n}$ = $\frac{11}{2}$ [2($\frac{1}{15}$) + (11 - 1) ( $\frac{1}{60}$ ) ]

• $\frac{11}{2}$ × [ ($\frac{2}{15}$) ] + ($\frac{1}{6}$) ]

❥ ${S}_{n}$ = $\frac{ 33 }{ 20 }$

➽ Sum of 11 terms of A. P. is $\frac{ 33 }{ 20 }$

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