Question 344014
Look at all of totality of outcomes.
There are {{{2^3}}} or {{{8}}} of them.
1.H H H
2.H H T
3.H T H
4.H T T
5.T H H
6.T H T
7.T T H
8.T T T
Now that you have all of the outcomes, you can answer all of your questions.

1. "at most two heads"-Means 2 H or less.
Count the number of outcomes that have 2 H or less.
There are 7 possible outcomes(2,3,4,5,6,7,8).
The probability is possible outcomes divided by total outcomes.
{{{P=7/8}}}
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2. At least 1 H- Again there are 7 of them (1,2,3,4,5,6,7)
{{{P=7/8}}}
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Now complete the remaining questions in a similar way.