Question

What is the average of 42 and 77?

Answer 1

42+77/2 = 119/2 = 59.5

Answer 2

$average \: of \: a \: and \: b \: is \: \frac{a + b}{2} \\ now \: \\ average \: of \: 42 \: and \: 77 \: is \\ \frac{42 + 77}{2} \\ = \frac{119}{2} = 56.5$
hope it helps.