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Mathematics
Mathematics
Problem
In an arithmetic progression the first term is
10
10
10
and the
n
n
n
th term is
70
70
70
. If the sum of the first
n
n
n
terms is
400
400
400
, then
n
n
n
equals a)
11
11
11
b)
10
10
10
c)
8
8
8
d)
4
4
4
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