Mathematics

Problem

a_p

and

a_q

are the

p

th and

q

th terms of an arithmetic progression (

p \neq q

), which of the following correctly gives the common difference

d

? a)

\dfrac{a_q - a_p}{q-p}

\dfrac{a_q - a_p}{q}

\dfrac{a_q - a_p}{p+q}

\dfrac{a_p - a_q}{q-p}