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# A level probability help!! Watch

1. hi, im kinda stuck on this please could anyone help and show the steps on how to solve this correctly:

When Betty is on holiday she intends to go for a five-mile run before breakfast every day. however sometimes she stays in bed instead. the probability that she will go for a run on the first morning is 0.8. thereafter, the probability that she will go for a run is 0.7 if she went for a run on the previous morning and 0.6 if she did not.

Find the probability that on the first three days of her holiday she will go for:

a) three runs
b) exactly two runs

thanks !!!!
2. For the first one you use the basic probability laws. , where A and B are independent.

For the second one, you also use this law, but you need to sum the different possibilities.

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Updated: January 14, 2015
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