Re: stats help needed

Yeah, do what Kennith said...
If you have a TI-83,84, etc:
There is a function called binompdf in the distribution menu (2nd, VARS)

The way it works: binompdf(# of trials, prob. of success, # of successes)

So the probability of seven trucks breaking down:
binompdf(100,.1,7)=0.0888952464

By the way, the probability that from 7 to 12 trucks out of service is: 0.6846654972 (that includes 7 and 12 trucks being out of service.

Good luck!
.