Question

find the sum of the first 15 multiples of 8 for class 10 th​

Answer 1

Answer:

960

Step-by-step explanation:

Let to be a is first term and 'd'" is common Difference and l is last term of Given Arithmetic Sequence or Progression;-

Arithmetic Sequence or Progression which are given below;-

Arithmetic Sequence or Progression;-

8,16,24,32....

Here,

First term= 8

CommOn Difference=8

Number of terms=15

We know that Formula of Summation of Arithmetic Sequence or Progression.

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

S15=15/2(2x8+(15-1)8

 =15/2(16+(14)8)

 =15/2(16+112)

 =15/2 x 128

 =15 x 64

=960

Hence ,960 are sum of the first 15 multiples of 8.

Answer 2

Answer:

960 is the answer

Step-by-step explanation:

8, 16 , 24, 32, 40, 48, 56, 64, 72, 80, 88, 96, 104, 112, 120 are the first 15 multiples of 8 .

So when they are added , they give 960

Hope it helps ☺️

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