我有一條題目唔識,係關於 Basic Algebra

1.There are p teachers and 20p students visiting a museum .The cost of an adult ticket
is$m and the cost of a student ticket is a that of an adult ticket.
(a)Express the cost of a student ticket by an algebra expression .

$m/2‧20p

(b) Express the total amount spent on buying the tickets by an algebra expression.

$m‧p+$m/2‧20p

student ticket = a x m = am
total amount = (p x m ) + (20p x a x m) = pm +20apm = pm (1+20a)