# calculate probability

#### littlesis1953

##### New member
Here i my problem. I am having a hard time figuring which formula to use.
Suppose that on a mountain pass they don't patrol the speed limit very often so that if you speed through there, you have only a 1% chance of getting ticketed. You might guess that Lightning McQueen has a 100% chance of getting at least one speeding ticket if he makes 100 trips through the pass, but this is incorrect. Calculate the probability Lightning gets at least one speeding ticket on his 100 trips. Round answer to a percentage with one decimal place.

#### pka

##### Elite Member
Here i my problem. I am having a hard time figuring which formula to use.
Suppose that on a mountain pass they don't patrol the speed limit very often so that if you speed through there, you have only a 1% chance of getting ticketed. You might guess that Lightning McQueen has a 100% chance of getting at least one speeding ticket if he makes 100 trips through the pass, but this is incorrect. Calculate the probability Lightning gets at least one speeding ticket on his 100 trips. Round answer to a percentage with one decimal place.
$$\displaystyle (.99)^{100}$$ is the probability that speedy gets no tickets. WHY?
So what is the probability he gets at least one?

Thank you.