A particular commodity has a price$-$demand equation given by

p $=$

$18,716415$x

$,$

where x is the amount in pounds of the commodity demanded when the price is p dollars per pound.

$($a$)$

Find consumers' surplus if the equilibrium quantity is $40$ pounds. $($Round your answer to the nearest cent if necessary.$)$

$

$($b$)$

Find consumers' surplus if the equilibrium price is $19$ dollars. $($Round your answer to the nearest cent if necessary.$)$

$