530 miles are travelled for every hour passed?
Answer: 715 ( C )
Explanation:
C (13,4) = (13!)/(4!*9!)
So it can be done on the calculator by 13C4
13! = 13 x 12 x 11 x 10 x 9 x 8 x 7 x 6 x 5 x 4 x 3 x 2 x 1
4! = 4 x 3 x 2 x 1
9! = 9 x 8 x 7 x 6 x 5 x 4 x 3 x 2 x 1
13 x 12 x 11 x 10 x 9 x 8 x 7 x 6 x 5 x 4 x 3 x 2 x 1 / ( 4 x 3 x 2 x 1 x 9 x 8 x 7 x 6 x 5 x 4 x 3 x 2 x 1 )
6,227,020,800 / 8,709,120
=715
So the correct answer is C, 715
Part 1:
You have the correct answer. You multiply the probability of getting red (6/15) by the probailitiy of getting red (6/15) to get 36/225 which reduces to 4/25
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Part 2:
This is also correct. Nice work. You multiply the probability of getting black (9/15) with the probability of getting red (6/15) to get 54/225 = 6/25
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Part 3:
The probability of picking a black checker is 9/15. If a replacement is made, then the probability of picking another black checker is also 9/15. So,
(9/15)*(9/15) = 81/225 = 9/25
Answer: 9/25
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Part 4:
The probability of rolling a 6 is 1/6. The probability of rolling a 3 is 1/6 as well. This is because there is only one side with this label out of 6 total. Multiply the probabilities
(1/6)*(1/6) = 1/36
Answer: 1/36
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Part 5:
It is impossible to roll a 7 on the six sided cube because the highest number is 6. Therefore the overall probability is 0
Answer: 0
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Part 6:
There are 3 outcomes we want (rolling a 1,2, or 3) out of 6 total. So the probability of rolling a 1,2 or 3 is 3/6 = 1/2. Similarly, the probability of rolling a 4, 5 or 6 is 3/6 = 1/2 as well.
Multiplying the probabilities gives
(1/2)*(1/2) = 1/4
Answer: 1/4
Answer:
Yosef finished the mile in 9 minutes.
Distance = 1 mile
Demetrius' speed = 7.5 miles per hour
Demetrius' time = Distance/speed
= 8 minutes
Demetrius finished the mile first by taking 1 minute less than Yosef's finishing time.