Math, asked by majajajoo8325, 7 months ago

What is the sum of first 10 terms of an A.P 41,36,31,26....?

Answers

Answered by pranavkumaryadav714
20

Answer:

P -----> 41, 36, 31, 26, ...........

So, First term = a = 41

d = 36 - 41 = - 5

n = 10

We know,

Sn = a + ( n - 1 ) d

S10 = 41 + ( 10 - 1 ) * (-5)

S10 = 41 + ( - 45 )

S10 = - 4

\huge\sf\blue{Hope\:it\:helps}

Answered by Anonymous
155

\huge{\underline{\underline{\red{\bf{Given:}}}}}

  • A AP is given , 41,36,31,26,21,.........

\rule{200}4

\huge{\underline{\underline{\red{\bf{To\:Find:}}}}}

  • The sum of first 10 terms of the AP .

\rule{200}4

\huge{\underline{\underline{\red{\bf{Concept\:Used:}}}}}

  • We will use formula to find the sum of n terms of AP .

\rule{200}4

\huge{\underline{\underline{\red{\bf{Answer:}}}}}

Given AP is 41,36,31,26,21,.....

Sum of this AP will be ,41+36+31+26+21.....+10terms.

Let the sum of AP be denoted by S.

Now sum of n terms of AP is given by ,

{\underline{\boxed{\red{\bf{\leadsto S_{n}=\dfrac{n}{2}[2a+(n-1)d]}}}}}

where

  • ☞ n is number of terms.
  • ☞ a is the first term.
  • ☞ d is the common difference.
  • \sf{S_{n}} is the sum of series.

Here ,

  • ☞ First term is 41.
  • Common Difference is (-5).
  • Number of terms = 10.

⇒S = 10/2 [ 2 ×41 +(10-1)×(-5)]

⇒S = 5 [ 82 + 9× (-5)]

⇒ S = 5 [ 82 -45]

⇒S = 5 × 37

⇒S = 185

Hence the required sum is 185.

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