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The sum of the 8th and the 15th non-zero multiple of 15 is
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1
Answer:
The multiples of 8 are 8,16,24,32…
These are in an A.P., having first term as 8 and common difference as 8.
Therefore, a=8,d=8, S
15
=?
S
n
=
2
n
[2a+(n−1)d]
S
15
=
2
15
[2(8)+(15−1)8]
=
2
15
[16+(14)(8)]
=
2
15×128
=960
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