Question

the sum of first 7 term of an ap is 63 and the sum of next 7 term is 161 find the 28 term of an ap

Answer 1

s7=63
s14=161
a28=?
sn=n/2*(2a+(n-1)d)
by using this Sn u will find 1st term and d value
then if u need to find 28th term
a28=a+(n-1)d
a28=a+27d
therefore u know first term and d value u can apply in this a28
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thank u