Question

Find the sum of 20 term of an AP whose nth term is 8n-5
2 points
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Answer 1

Answer:

the sum of 20thterm of the given AP is 1,580.

S20=?.

an=8n-5

a1=8(1)-5

a1=8-5

a1=3

a2=8(2)-5

a2=16-5

= 11

d= a2-a1

d=11-3

d=8

s20=20/2[2(3)+(20-1)8]

=10[6+(19)8]

=10[6+152]

=10[158]

s20=1580