An electric device delivers a current of [tex]$15.0 A$[/tex] for 30 seconds. How many electrons flow through it?
Answer (2)
Inequality 1 is incorrect because Kyle's grandmother's age is not more than 80, meaning g ≤ 80 .
Inequality 2 is correct as the grandmother's age is at most 3 years less than 3 times Kyle's age, represented by g ≤ 3 k − 3 .
Jane wrote Inequality 1 as 80"> g > 80 , which contradicts the given information.
The correct Inequality 1 should be g ≤ 80 , indicating the grandmother's age is less than or equal to 80. I n e q u a l i t y 1 i s in correc t ; i t s h o u l d b e g ≤ 80.
Explanation
Problem Analysis Let's analyze the given information to determine which inequality Jane wrote incorrectly.
Analyzing Inequality 1 Kyle says his grandmother is 'not more than 80 years old'. This means her age is less than or equal to 80. So, the correct inequality should be g ≤ 80 . Jane wrote 80"> g > 80 , which is incorrect.
Analyzing Inequality 2 Kyle also says his grandmother's age is 'at most, 3 years less than 3 times his own age'. This means her age is less than or equal to 3 k − 3 . So, the inequality g ≤ 3 k − 3 is correct, and Jane wrote it correctly.
Conclusion Therefore, Inequality 1 is incorrect, and it should be g ≤ 80 .
Examples
Understanding inequalities is crucial in various real-life scenarios. For instance, when planning a budget, you might say your expenses ( e ) should be 'no more than' your income ( i ), which translates to the inequality e ≤ i . Similarly, if a store offers a discount of 'at least' 20%, and the discount amount is d , then d ≥ 0.2 p , where p is the original price. These simple inequalities help us make informed decisions in everyday situations.
In this scenario, a current of 15.0 A flowing for 30 seconds results in a charge of 450 C . Using the charge of a single electron, we find that approximately 2.81 × 1 0 21 electrons flow through the device. This showcases the relationship between current, charge, and the flow of electrons in electric circuits.
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