Question

The sum of first 10 terms of the AP 10,7,4…... is………​

Answer 1

Answer:

Sn = -35

let Sn be the sum of n terms.

using formula....

Sn = n/2 [2a+(n-1)d]

Sn = 10/2 [2×10+(10-9)-3]

Sn = 5[20-27] = -35

Sn = -35

Answer 2

The sum of first 10 terms of the AP 10,7,4…... is  -35.

The given Arithmetic Progression (AP) is 10,7,4...

First term (a) = 10

Common difference between 2 terms (d) = 7 - 10 = -3

We know that, sum of first n terms in AP is given as:

Sn = (n/2)[2a + (n-1)d]

To find the sum of first 10 terms, we take n as 10.

So,

S = (10/2)[20 + 9*(-3)]

= -35

This is the required answer.