Probability Question Based on Both, Neither or At Least One

[baily106]

Hello,

I am referring to question #15 on page 298 of The Official Guide. The question states, "Lin and Mark each attempt independently to decode a message. If the probability that Lin will decode the message is 0.80 and the probability that Mark will decode the message is 0.70, find the probability that a) both will decode the message, b) at least one of them will decode the message, c) neither of them will decode the message. I understand the answer for part a), but don't understand parts b) or c).

Thanks.

[baily106]

Nevermind; I figured this out.

[tommywallach]

Cool. Sorry I didn't respond sooner. There seems to have been a problem with the forum putting them through for my account. Usually I'm not quite so slow!

-t

[baily106]

Yes, I know.
You've been pretty quick with your responses in the past.

[tommywallach]

I try, anyway!