Question

Find the fourth term from the end in an a. P. -11,-8,-5,.....49.

Answer 1

from given a=-11 and a2=-8 for the common difference d = a2- a
then we get d=3
first we have to find how many observations are in the a.p
for that we have formula
on subistute the values in the formula we get observations that is 21
given from the end so first we have to subtract 4 from 21 then we get 17
to this we have to add 1 because given its from end
substitute the values in the formula
we get

the fourth term from the end in an a.p is 40
I hope this is correct and helps you