Answer:
Your answer should be 4...
Explanation:
In the first time you planted, you planted 10 total bulbs, and 8 of them bloomed. That means that 80% of the bulbs that you planted bloomed. So if you plant 5 more bulbs, theoretically your answer should be 4, since 80% of 5 is 4.
I'm sorry if this answer isn't a lot of help, there isn't a lot of information to go off of.