American Girl In An ECONOMICS TEXTBOOK?

Today I learned there's an American Girl themed problem in some economics textbook. Here it is:

"Suppose the doll company American Girl has an inverse demand curve of P = 150 – 0.25Q, where Q measures the quantity of dolls per day and P is the price per doll. The marginal cost is given by MC = 10 + 0.50Q. What is the total surplus at the profit-maximizing output level?"

I don't really understand economic math problems, but I thought it was funny that there's an AG problem in a textbook! Besides, there's nothing better to post.