149x15=2235. If there were 8 duds in 149 it averages a dud every 18 firecrackers. So we know there's 2086 more so we for sure know there is more than 10 most likely more than 15 I'm assuming 15-30 so if there are any answers in that range I think it could be the answer (if more than one answer is in that range let me know and I'll try figuring out the exact answer)
