Question

If the 8th term of an appointment is 31 and the 15th term is 16 more than 11th term, find the ap

Answer 1

tn= a+(n-1)d=
t8=a+(8-1).d
31=a+7d(1) equ
t15=a+(15-1)d
16=a+14d(2) equ
(1)-(2)
a+7d=31
a+14d=16
-0-7d=-15
d=15/7
d ko equa(1) in
a+7d=31
a=31-7d
a=31-7.15/7
a=31-15
a=6
tn=a+(n-1)d
t11= 6+(11-1)15/7
t11=6+10.15/7
t11=6+150/7
t11=192/7
t11=27.2
t11=27 answer