Answer:
12 minutes
Step-by-step explanation:
Candles can be manually packed at the rate of ...
... (400 candles)/(36 minutes) = 11 1/9 candles/minute
The two systems together pack candles at the rate of ...
... (400 candles)/(9 minutes) = 44 4/9 candles/minute
Then the machine's packing rate is the difference between the total and the manual rates:
... machine rate = (44 4/9 candles/minute) - (11 1/9 candles/minute)
... = 33 1/3 candles/minute.
At this rate, the machine working alone can pack 400 candles in ...
... (400 candles)/(33 1/3 candles/minute) = (400/(100/3)) minutes
... = 400 × 3/100 minutes = 12 minutes
Answer:
y=10
Step-by-step explanation:
1.7y+37 is 14 less than the value of 9.3y–25
- 1.7y + 37 = 9.3y - 25 - 14
- 1.7y + 37 = 9.3y - 39
- 9.3y - 1.7y = 37 + 39
- 7.6y = 76
- y = 76/7.6
- y = 10
Answer is 10
Answer:

Step-by-step explanation:
Circumference of the column 
Circumference of a circle
Therefore:

Area of a Circle 
Since radius of the cross section of the column =9 meters
Area of the cross section of the column

Then, 15 - x is the distance ran in the second part.
The time, t1, for the first part is t1 = xmi / 8mi/h
The time, t2, for the second part is t2 = (15 - x)mi / 20mi/h
The total time is t1 + t2 = 1.125 h
Then x/8 + (15 - x) / 20 = 1.125
To solve for x, multiply both sides by 40 (this is the least common multiple)
5x + 30 - 2x = 45
3x = 15
to find x divide: 15/3=5
And 15 - x = 10 mi.
First part:
Speed: 8mi/h
Distance: 5 mi
Time: 5mi/8mi/h = 5/8 h = 37.5 minutes
Second part
Speed: 20 mi/h
Distance: 10 mi
Average speed: 15mi/1.125h =13.33 mi/h
Distance: 15mi
Time: 1.125 h = 67.5 minutes
Answer:
Step-by-step explanation:
Given is the probability distribution of a random variable X
X 4 5 6 7 Total
P 0.2 0.4 0.3 0.1 1
x*p 0.8 2 1.8 0.7 5.3
x^2*p 3.2 10 10.8 4.9 28.9
a) E(X) = Mean of X = sum of xp = 5.3

Std dev = square root of variance = 0.9
------------------------------------
b) For sample mean we have
Mean = 5.3
Variance = var(x)/n = 
c) 