This is the easiest way to solve this problem:
Imagine this represents how many combinations you can have for each of the 4 wheels (each blank spot for one wheel): __ __ __ __
For the first situation it says how many combos can we make if no digits are repeated.
We have 10 digits to use for the first wheel so put a 10 in the first slot
10 __ __ __
Since no digit can be repeated we only have 9 options for the second slot
10 9_ __ __
Same for the third slot, so only 8 options
<u>10</u> <u> 9 </u> <u> 8 </u> __
4th can't be repeated so only 7 options left
<u>10</u> <u> 9 </u> <u> 8 </u> <u> 7
</u><u>
</u>Multiply the four numbers together: 10*9*8*7 = 5040 combinations
For the next two do the same process as the one above.
If digits can be repeated? You have ten options for every wheel so it would look like this: <u>10</u> <u>10</u> <u>10</u> <u>10
</u>
10*10*10*10 = 10,000 combinations
If successive digits bust be different?
We have 10 for the first wheel, but second wheel only has 9 options because 2nd number can't be same as first. The third and fourth wheels also has 9 options for the same reason.
<u>10</u> <u> 9</u><u> </u> <u> 9 </u> <u> 9 </u>
10*9*9*9 = 7290 combinations
7. 18.3 divided by 4 is 4.575. 4.575 is closest to 4.5 which would be our answer
8. 14.6 divided by 3 is 4.86. If we round it, then it would be 5 which would be the answer
10. The answer to the problem would be 11.58
The terminal side means that it's 16 to the right and 12 up. Which means that the triangle made from this has the sides of 16 and 12 and the hypotenuse is 20 units long. Theta, in this case, would have 16 as it's adjacent and 12 as it's opposite.
Therefore, using the Pythagorean identities:
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If the teacher isn't putting the names back in the hat then it would be 1/21 if she is then 1/23