Can anyone help with this econ question?

Jules would like to buy a Royal with Cheese from Vincent at the Big Kahuna Burger

shop. Vincent is willing to o铿€er this tasty burger to Jules for $3. Jules is willing

to pay $8 for this tasty burger (his girlfriend is a vegetarian so he does not get

the opportunity to eat many tasty burgers). How large are the potential gains from

trade if Jules and Vincent agree to make this trade? That is, what is the total surplus

(consumer and producer) generated if the tasty burger exchanges hands?Can anyone help with this econ question?
The potential gain from trade is the absolute difference between Jules's ($8) maximum willingness to spend and Vincent's minimum willingness to sell ($3). Hence the gain from trade will be $5.



Thought of another way, assuming Jules and Vincent are rational, the final price of the burger will between $3 and $8, as Jules will not take a price below $3 and Vincent will not offer to pay above $8. So P, the price of the burger, will fall in the range $3%26lt;P%26lt;$8. Vincent's consumer surplus is his maximum willingness to pay less the price, expressed as $8-P. Jules's producer surplus is likewise P-$3. Thus total surplus is $8-P+P-$3 = $5.