Consider the estimated demand function for$$ avocados:

Q$=104$ minus $40$p$+20$p Subscript t $+0\mathrm{.}01$Y$,$

where Q is the quantity of avocados demanded$($measured in millions of lbs per$$ year$),$ p is the price of$$ avocados, p Subscript t is the price of$$ tomatoes, and Y is the income of consumers.$($Note: The price of$$ tomatoes, p Subscript t$,$ is$$ $$1\mathrm{.}00.)$