Cuz They Are Identical Duhhh
Answer:
C. 
Step-by-step explanation:
BD = DC because angles ADC and ADB are right angles.
Thus, 
Add 5 to both sides:
Subtract 2x from both sides:
Divide both sides by 2:
DC 
Answer:
Average is 22.72
Step-by-step explanation:
Let's assume there's a fourth place too, and fourth place is the one where it's no prize.
4 3 2 1 (4 3 X X)
4 3 1 2 (^ but 3rd and 4th digit exchanged)
4 2 3 1 (4 2 X X)
4 2 1 3 etc.,.
4 1 2 3
4 1 3 2
As you can see, there are six possibilities assuming first swimmer was fourth.
Now, there would be six possibilities if the first swimmer was third, and same goes for second and first.
Thus, 6 x 4 = 24, there are 24 possibilities to award the 3 prizes (plus 1 no-prize)
Simple Mathematical Way:
4 x 3 x 2 x 1 = 4! = 24
There are 24 ways.
I'm pretty sure it is 25. A method you could use(calculator would be more quicker, but by hand works too) is dividing 15 by sixty percent. To do that, u find the decimal of sixty percent. You would move the decimal point of sixty(the original place of the decimal would be 60.0) two places to the left. Then 60% would become 0.60. But, you could simplify that to 0.6, then you do 15 divided 0.6. You would get 25. If you are doing it by hand, double check the answer by multiplying it with the decimal and you should get the original number(which is 15 in this case). I hope this helped :)
