Question

The sum of first 8 terms is 100 and sum of first 19terms is 551 find ap

Answer 1

Answer:

Given,

s8=100;s19=551

Sn=n/2(2a+(n-1)d)

S8=4(2a+7d)=100

=>2a+7d=25

=>a=(25-7d)/2.........1

S19=19/2(2a+18d)=551

=>19(a+9d)=551

=>a+9d=29

=>(25-7d+18d)/2=29

=>25+11d=58

=>11d=33

=>d=3

Subs d in 1

a=(25-21)/2

a=2

Therefore ap= 2,5,8,....

Hpe it hlps u