The first and second terms of an arithmetic progression are p and q respectively. Find the tenth term
Hint: the terms of an arithmetic progression are given by $\displaystyle a_n = a_1 + (n - 1)d$ for $\displaystyle n \in \mathbb{N}$
where $\displaystyle a_n$ is the nth term, $\displaystyle a_1$ is the first term, $\displaystyle n$ is the current number of the term, and $\displaystyle d$ is the common difference
now, $\displaystyle d = a_2 - a_1 = a_3 - a_2 = ...$