The first and the last terms of an A.P. are 8 and 350 respectively. If its common difference is 9, how many terms are there and what is their sum?
OR
How many multiples of 4 lie between 10 and 250? Also find their sum
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Answered by
8
Answer:
Hi
Step-by-step explanation:
a=8, an= 350, d=9, Sn=?, n=?
an= a+(n-1)d
350=8+(n-1)9
342=(n-1)9
38=n-1
39=n
Sn=n/2(a+l)
= 39/2(8+350)
=39/2*358
=39*179
=6981
Answered by
0
find number of terms=n, sum=Sn
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