1. there are 4 bikes and 6 parking spaces. in how many different ways can 4 bikes be parked. 2. How many different signals, each consisting of 6 flags hang in a vertical line, can be formed from 4 identical red flags and 2 identical blue flags.

3. How many 3-letter words can be formed from the word Smile if each has to start with an S or E.

4. There are 6 different designs of wrapping paper and 4 colors of ribbon. In how many different ways can a gift be wrapped?
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