The sum of first four terms of an Ap is56 the sum of last four terms is 112.if its first term is 11 the number of terms is
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Answered by
7
s4=4/2(22+3d)
56=2(22+3d)
28=22+3d
6=3d
d=2
Sn=n/2(22+(n-1)2)
112=n/2(22+2n-2)
224=n(20+2n)
224=2n^2+20n
then solve it
divide by 2
112
56=2(22+3d)
28=22+3d
6=3d
d=2
Sn=n/2(22+(n-1)2)
112=n/2(22+2n-2)
224=n(20+2n)
224=2n^2+20n
then solve it
divide by 2
112
Answered by
1
is the number of terms is 10
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