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Helga [31]
3 years ago
7

A tank can be filled by one pipe in four hours and by a second pipe in six hours; and when it is full, the tank can be drained b

y a third pipe in three hours. If the tank is empty and all three pipes are open, in how many hours will the tank be filled?
8 hours
12 hours
24 hours
Mathematics
2 answers:
disa [49]3 years ago
8 0

Answer:

12 hours

Step-by-step explanation:

Let t be time to fill with all pipes open

All the pipes will complete a single job that is = 1

Given is that the tank can be filled by one pipe in 4 hours and by a second pipe in 6 hours and can be drained by a third pipe in 3 hours.

So, equation forms;

\frac{t}{4}+ \frac{t}{6}- \frac{t}{3}=1

=> \frac{3t+2t-4t}{12} =1

=> \frac{t}{12} =1

And t = 12 hours

Hence, it will take 12 hours to do the job.

just olya [345]3 years ago
3 0
12 hours..........
+ - = 1
Multiply by 12 to clear the fractions
3t + 2t - 4t = 12
t = 12 hrs to fill the pool
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The question is not complete and the full question says;

Calculate the (a) range, (b) arithmetic mean, (c) mean deviation, and (d) interpret the values. Dave’s Automatic Door installs automatic garage door openers. The following list indicates the number of minutes needed to install a sample of 10 door openers: 28, 32, 24, 46, 44, 40, 54, 38, 32, and 42.

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Step-by-step explanation:

A) In statistics, Range = Largest value - Smallest value. From the question, the highest time is 54 minutes while the smallest time is 24 minutes.

Thus; Range = 54 - 24 = 30 minutes

B) In statistics,

Mean = Σx/n

Where n is the number of times occurring and Σx is the sum of all the times occurring

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C) Mean deviation is given as;

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The number of minutes the time deviates on average from the mean of 38 minutes is 7.2 minutes

4 0
3 years ago
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Answer:

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Step-by-step explanation:

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x= 24/30.48 =0.7874 feet

Side D is 0.78 feet (to 2 s.f.)

7 0
3 years ago
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