Long/short market neutral HF strategy only, understand, solution, example

burning0spear

Is it just me?...
Re: example 7, pg. 208 Vol 6...w/ margin can invest $50m, "solution" invests $25m long (@5%) and $25m short (@5%) but earns 10% on 50m?...I don't get it.

In the quiz (Ques.#14, pg 235, answer page A-23)...w/margin can invest $120m, goes 120m (@7%) long and 120m(@7%) short, earns 14% on 120m...this I understand.

Is it just me, or does the "solution" for example 7 seem incorrect? Shouldn't they invest 50m long AND 50m short to get 10% on 50m? Otherwise, wouldn't they only earn 10% on 25m? (and not be as invested as they could be?)