# Probability help! Am I even doing this right?

I am really bad with probability, so I just want some explanations and help with this problem (and probably many more to come!) and I also want to know if I am on the right track. Thank you!

Lyme disease is a disease carried by ticks, which can be transmitted to humans by tick bites. Suppose the probability of contracting the disease is 1/100 for each tick bite.

a. What is the probability that you will not get the disease when bitten once?

I know that the probability of NOT getting the disease is 99/100, so if it is one time you get bitten, then the probability that you will not get the disease when bitten once IS 99/100, right? Since it is only one time.

b. What is the probability that you will not get the disease from your first tick bite, and will the it from your second tick bite?

I did (probability of NOT getting the disease) x (probability of getting the disease). So I got (99/100) x (1/100) = 99/10000 as the answer. Am I correct? I think the events are independent from each other.

• If they are independent, then you are on the right track. – JohnWO Oct 8 '14 at 23:48
• The two answers are correct. You're not correct about being really bad with probability. Perhaps you're a little bad (although there is nothing here to support that either), but you're most likely not really bad. – barak manos Oct 8 '14 at 23:58