If in an A.P, 3rd term is 18 and 17th term is 60, then the sum of its first 17 terms is
Answers
Answered by
14
Explanation is given below
See the attachment
Attachments:
Answered by
8
Answer:
s17=612
Step-by-step explanation:
t3=18
t17=60
a+2d=18
a+16d=60
By elimination method
14d=42
d=42/14
d=3
sub d=3
a+2d=18
a+6=18
a=12
s17=?
n=17
s17=n/2(2a+(n-1)d)
=17/2(2*12+(17-1)*3)
=17/2(24+48)
=17/2(72)
=17*36
=612
Similar questions