Answer:
Mean is 81%
standard deviation is approximately 4.2%
Step-by-step explanation:
Since the number of boys equals the number of girls, but it is not given, we name it "N". and proceed to calculate the mean as:
Mean = (0.78 * N + 0.84 * N) /(2 N)
using that the total number of students must be N boys + N girls = 2 N
Then the Mean becomes: N *(0.78 + 0.84) /(2 N) = (0.78 + 0.84) / 2 = 1.62 / 2 = 0.81
So the mean is 81%
Now, standard deviation will be calculated by first adding the squares of the deviations: (X-0.81)^2 for the N boys and for the N girls, and then finding the square root of this and finally dividing by the square root of N. That is:

Now finding the square root of this value, and finally dividing it by the square root of N:

which in percent form is: approximately 4.2%
Answer: Each cup of hot chocolate is $3.25
Step-by-step explanation:
Answer:
x represents the number of level 1 tickets; y represents the number of level 2 tickets
Step-by-step explanation:
The first equation (x + y = 1,000
) shows that x + y equal to the number of seats in the auditorium. That means that they represent the number of tickets. In the second equation (75x + 100y = 25,000) x and y are being multiplied by the cost of their level ticket. So x represents the number of level 1 tickets; y represents the number of level 2 tickets.
hope this helps!
Answer: An equation we can use to find the number of djembe drums you sold be

Step-by-step explanation:
Let price of maracas be m
Let the price of claves be c
Let the price of djembe drums be d
Number of maracas = 12 sets
Number of clavas = 6 sets
Number of djembe drums be xx
Total earned amount = $326
According to question,

Hence, an equation we can use to find the number of djembe drums you sold be

3 x 4 is equal to 12 I think that’s your answer