To evaluate the combination we proceed as follows:
21C3
Given nCk we shall have:
n!/[(n-k)!k!]
thus plugging the values in the expression we get:
21!/[(21-3)!3!]
=21!/(18!×3!)
=1330
Answer: 1330
You could do V = b × H 2 × 11 = 22
Answer: 3/4, because the probability of renting a comedy is 1/4
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Explanation:
We have 36+26+30+28 = 120 students. 30 of which rented a comedy.
The probability of renting a comedy is 30/120 = (30*1)/(30*4) = 1/4
The probability of not renting a comedy is 1 - (1/4) = 4/4 - 1/4 = (4-1)/4 = 3/4.
Or you could say that 1/4 = 0.25, so 1-0.25 = 0.75 which converts to the fraction 3/4.
If you had 4 people and 1 of them rents a comedy, then the other 3 hasn't rented a comedy.
Answer:
15
Step-by-step explanation:
gradient=(change in Y coordinate/change in X coordinate)
=y1-y2/X1-X2
Answer:
<em>Shayla charges $20 per hour for middle school students and $25 per hour for high school students.</em>
Step-by-step explanation:
<u>System of Equations</u>
Let's call:
x = Shayla's hourly charge for middle school students
y = Shayla's hourly charge for high school students
Last week, Shayla tutored middle school students for 5 hours and high school students for 12 hours. The total earning was 5x+12y. She earned $400 last week, thus:
5x + 12y = 400 [1]
This week, she tutored middle school students for 6 hours and high school students for 10 hours. The total earnings were 6x+10y and it represented $370, thus:
6x + 10y = 370
Dividing by 2:
3x + 5y = 185 [2]
We have formed the system of equations:
5x + 12y = 400 [1]
3x + 5y = 185 [2]
Multiply [1] by -3 and [2] by 5:
-15x - 36y = -1200
15x + 25y = 925
Adding both equations:
-11y = -275
Dividing by -11:
y = -275/(-11) = 25
y = 25
Substituting in [1]:
5x + 12*25 = 400
5x + 300 = 400
5x = 400 - 300 = 100
x = 100/5 = 20
x = 20
Shayla charges $20 per hour for middle school students and $25 per hour for high school students.
