Solution:

17 min

The initial solution most people will think of is to use the fastest person as an usher to guide everyone across. How long would that take? 10 + 1 + 7 + 1 + 2 = 21 minutes. Is that it? No. That would make this question too simple even as a warm up question.

Let's brainstorm a little further. To reduce the amount of time, we should find a way for 10 and 7 to go together. If they cross together, then we need one of them to come back to get the others. That would not be ideal. How do we get around that? Maybe we can have 1 waiting on the other side to bring the torch back. Ahaa, we are getting closer. The fastest way to get 1 across and be back is to use 2 to usher 1 across. So let's put all this together.

1 and 2 go cross
2 comes back
7 and 10 go across
1 comes back
1 and 2 go across (done)

Total time = 2 + 2 + 10 + 1 + 2 = 17 minutes

Solution:

Draw a tilted line on 1st plus (+) operator, + will become 4 :-)
The equation then becomes true: 545+5=550.

Solution:

888+88+8+8+8=1000

Solution:

A and W.

The letters are the first letters of the words in the question. Thus, the next two letters are A and W.

Solution:

2100 miles.

Each vowel equivalent to 500 and each consonant equivalent to -200

Solution:

They're both in the middle of wa'T'er

Solution:

Because seven was hungry and 'seven ate nine' (7, 8, 9).

Solution:

888 + 88 + 8 + 8 + 8 = 1000

Solution:

41312432

Solution:

Each word rhymes with its numeric position in the list. (e.g. 'gun' rhymes with 'one', etc.)