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**JaneDyan****Guest**

Please help me with this problem:

An oil-prospecting firm plans to drill 2 exploratory wells. Past evidence shows that the probability that neither well produces oil is 0.8; the probability that exactly one well produces oil is 0.18; and the probability that both wells produces is 0.02. What is the probability that at most one well produces oil? At least one?

**bobbym****Administrator**- From: Bumpkinland
- Registered: 2009-04-12
- Posts: 86,776

Hi JaneDyan;

Welcome to the forum.

What is the probability that at most one well produces oil?

That can mean 0 or 1 so

.8 + .18 = .98

At least one?

That means 1 or 2 which is the complement of none.

1 - .8 = .2

**In mathematics, you don't understand things. You just get used to them.Of course that result can be rigorously obtained, but who cares?Combinatorics is Algebra and Algebra is Combinatorics.**

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**JaneDyan****Guest**

Thank you very much!

Following the manner on how you solve the problem, I realized that the first question could also be answered by

getting the complement/not the probability of both wells producing oil:

1-.02=0.98

**bobbym****Administrator**- From: Bumpkinland
- Registered: 2009-04-12
- Posts: 86,776

Hi JaneDyan;

Yes, that is another way of getting it.

**In mathematics, you don't understand things. You just get used to them.Of course that result can be rigorously obtained, but who cares?Combinatorics is Algebra and Algebra is Combinatorics.**

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