Answer:
22.22%
Explanation:
Currently Rainbow's stocks are priced at $36 per stock.
If the holder can convert his $1,100 bond into 25 stocks, that means that each stock should be worth at least $44 (= $1,100 / 25).
So the current stock price should increase by $8 (= $44 - $36) in order for a trade to be attractive, $8 represents a 22.22% increase (= ($8 / $36) x 100)