Downside Risk, page-45

Company A has 10 issued shares, net assets of $100 and a dividend of $5 is paid per year in total - it trades at $10 a share (which conveniently equals Net Assets per share) and a div yield of 5% ($0.50/$10)
Company B has 100 issued issued shares, net assets of $100 and a dividend of $5 is paid in total - it trades at $1 a share (again conveniently net assets per share) and has a yield of 5% ($0.05/$1).

Both companies find $100 on the side of the road (Gambian sea) and are allowed to keep it.

What do the shareprices of both companies do? Please explain why the share prices of both companies dont both double or at least change by the same %.

In my book both would double in shareprice as the market cap would double for both, yet the shares on issue hasn't changed, causing a doubling of the shareprice.