Attached is a question for an upcoming exam, I have worked through it already but could use a second opinion. Thank you.

Charlie Chump had collected coins for year.He amassed a fairly good collection and then essentially forgot about it in his attic.Several years later he came across the collection as he was reorganizing his attic.He no longer had any interest in keeping the collection.He called his friend Steve Slick to look at the collection and see if had any interest in buying the whole collection.Charlie had forgotten that the collection included some solid gold eagle coins.Steve came to Charlie's house and reviewed the collection.Steve noticed the gold coins but didn't mention it to Charlie.Steve said, "There is not much here that I really want but I will offer you $400 for the whole collection".Steve said I was hoping for a little more.Steve said "I will give you $450.Charlie said "we have a deal"

A couple days later, Charlie noticed that his gold coins were gone, included in the collection.Charlie asked for them back.Steve said they were included in the collection.

Charlie filed suit to rescind (cancel) the contract. What result and why?