Question

The sum of 10 terms of 5+8+11+....

Answer 1

ANSWER =

Sn = ?

n= 10
a = 5
d = 8 - 5
= 3

FORMULA : Sn = n/2 ( 2a + (n-1) d)

Sn = 10/2 [ 2 x 5 ( 10 - 1 ) 3 ]

Sn = 5 ( 10 x 9 x 3 )

Sn = 5 x 10 x 9 x 3

Sn = 1350

sum = 1350



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Answer 2

HEY!
_______

$s_{n} = \frac{n}{2}(2a + (n - 1)d)$
Here,

a = 5

d = 8 - 5 => 3

n = 10

$s_{n} = \frac{10}{2}[2 × 5 + (10 - 1)3]$

$s_{n} = 5 [ 10 + 9 × 3]$

$s_{n} = 5 [ 10 + 27 ]$

$s_{n} = 5 × 37$


$s_{n} = 185$