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Oliga [24]
3 years ago
15

In how many ways can a teacher arrange 5 students in the front row of a classroom with a total of 20 students?

Mathematics
2 answers:
Nezavi [6.7K]3 years ago
6 0
In the first chair in front row, the teacher can choose from 20 students. She can choose from the remaining 19 to be seated in the 2nd chair. 18 for the 3rd chair. 17 for the 4th chair and lastly 16 for the 5th chair. The number of ways is the product of all these numbers. Thus, the teacher can arrange them in 1860480 ways. 
aksik [14]3 years ago
5 0
Slot method
5 slots

1st slot: 20
2nd slot: 19 (1 went to first slot)
3rd slot: 18
4th slot: 17
5th slot: 16

20*19*18*17*16=186,040 ways
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Person 1 writes internal operating procedures 3 times faster than Person 2. Most of the procedures took 30 minutes each to creat
ad-work [718]

Person 1 takes 3 hour 10 minutes to complete 9 procedures

<em><u>Solution:</u></em>

From given question,

Person 2 takes 30 minutes per procedure

Person 1 writes internal operating procedures 3 times faster than Person 2

So we get, Person 1 takes 3 times faster than Person 2

Person 1 takes 10 minutes per procedure

But two of the procedures for Person 1 took an hour each

So person 1 takes 60 minutes each for two of procedures ( since 1 hour = 60 minutes )

<em><u>Calculate how long it took Person 1 to complete 9 procedures:</u></em>

So for first 7 procedures person 1 would take 10 minutes per procedure and for last two procedures person 1 would take 60 minutes per procedure

time $=7$ procedures $\times \frac{10 \text { minutes }}{1 \text { procedure }}+2$ procedure $\times \frac{60 \text { minutes }}{1 \text { procedure }}$

time=70 minutes +120minutes\\\\time=190minutes

We know that,

1 hour = 60 minutes

Therefore,

190 minutes = 60 minutes + 60 minutes + 60 minutes + 10 minutes

190 minutes = 1 hour + 1 hour + 1 hour + 10 minutes = 3 hour 10 minutes

Therefore Person 1 takes 3 hour 10 minutes to complete 9 procedures

7 0
3 years ago
What is the product of 2x-5 and 3x2 + 5x - 7? Write your answer in standard form.
jasenka [17]

Step-by-step explanation:

this is your answer..........

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3 years ago
What is the equation of a parabola with a focus (-2,4) and directrix y = 0?
Ronch [10]
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Given a focus of (-2,4) and a directrix of y = 0, we can assume the vertex of the parabola is exactly half way in between the focus and the directrix.  The focus and vertex with be stacked one above the other, therefore the vertex will be (-2, 2) and the value of 'p' will be 2.  We can now write the equation of the parabola:
(x + 2)² = 4(2)(y - 2)
(x + 2)² = 8(y - 2)  Now you can solve this equation for y if you prefer solving for 'y' in terms of 'x'
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Answer:

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The function shown is in the form y = (x - h)^2. Determine the value of h. A) -1 B) 1 C) 2 D) - 1/ 2
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