Question

If the sum of a certain number of terms of the AP 25,22,19,... is 116.Find the last term.

Answer 1

Good Day Joyal, the arithmetic pogression has a formula that you may be able to use:\[a_{n} = a_{m} + (n-m)(d)\]
\[s = \frac{ n }{ 2 } (a _{1} + a _{n})\]

now for you to be able to solve the problem you should fist understand which on the given you will be using to substitute on the formula

Answer 2

on the given formula:

n = no. of terms
a sub m = any term before a sub n
a sub n = last term
m = position of a sub m in the progression.
d = gap between the progressing numbers

Now begin to substitute using my formula, good luck. I hope this helps.