Question

One of the rules in a public speaking contest requires contestants to speak for as close to 5 minutes (300 seconds) as possible. Contestants lose 3 points for each second they speak either over or under 5 minutes. Which expression below can be used to determine the number of points a contestant loses if she speaks for x seconds?

• A. $3|x-300|$
• B. $5|x-300|$
• C. $3|x+300|$
• D. $\frac{3}{5}|x+300|$

Answer 1

The correct option is A $3|x-300|$

Solution:
Step I :Underline the key words/facts
One of the rules in a public speaking contest requires contestants to speak for as close to 5 minutes (300 seconds) as possible. Contestants lose 3 points for each second they speak either over or under 5 minutes. Which expression below can be used to determine the number of points a contestant loses if she speaks for x seconds?

Step II : Recognize the variable
Time taken by a contestant = x seconds

Step III : Form the equation
Here the critical point is 300 seconds.
The number of seconds above or below 300 seconds that a contestant speaks for is $|x-300|$
Therefore, the number of points a contestant loses is $3|x-300|$