IM: 7.5.14: Solving Problems with Rational Numbers (Lesson)
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Last updated about 1 year ago
8 questions
14.1: Which One Doesn’t Belong: Equations
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14.2: Draining and Filling a Tank
14.3: Buying and Selling Power
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Question 8
8.
Question 1
1.
A tank of water is being drained. Due to a problem, the sensor does not start working until some time into the draining process. The sensor starts its recording at time zero when there are 770 liters in the tank.
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A utility company charges $0.12 per kilowatt-hour for energy a customer uses. They give a credit of $0.025 for every kilowatt-hour of electricity a customer with a solar panel generates that they don't use themselves.
A customer has a charge of $82.04 and a credit of -$4.10 on this month's bill.
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Find the value of the expression without a calculator.
(2)(-30)+(-3)(-20)+(-6)(-10)-(2)(3)(10)
Then, write an expression that uses addition, subtraction, multiplication, and division and only negative numbers that has the same value.
Which equation doesn’t belong?
\frac{1}{2}x-50
-60t=30
x+90=-100
-0.01=-0.001x
Question 2
2.
Given that the drain empties the tank at a constant rate of 14 liters per minute, complete the table:
Question 3
3.
Later, someone wants to use the data to find out how long the tank had been draining before the sensor started. Complete this table:
Question 4
4.
If the sensor started working 15 minutes into the tank draining, how much was in the tank to begin with?
Question 5
5.
What is the amount due this month?
Question 6
6.
How many kilowatt-hours did they use?
Question 7
7.
How many kilowatt-hours did they generate that they didn't use themselves?