Answer:
E. 16 min 12 sec
Step-by-step explanation:
Let x represent total time taken to complete the exercise.
We have been given that Dara ran on a treadmill that had a readout indicating the time remaining in her exercise session.
When the readout indicated 24 min 18 sec, she had completed 10% of her exercise session. This means that 90% time of exercise is equal to 24 minutes and 18 seconds.
18 seconds will be equal to 0.3 minutes.
Let us find total time of exercise as:
[tex]\frac{90}{100}x=24.3[/tex]
[tex]0.90x=24.3[/tex]
[tex]\frac{0.90x}{0.90}=\frac{24.3}{0.90}[/tex]
[tex]x=27[/tex]
To find readout when Dara had completed 40% of her exercise session, we need to find 60% of total time.
[tex]\frac{60}{100}(27)=0.60(27)=16.2[/tex]
Since our time in in minutes, so we will convert 0.2 minutes to seconds by multiplying by 60.
[tex]0.20(60)=12[/tex]
Therefore, the readout will indicate 16 minutes 12 seconds, when Dara had completed 40% of her exercise session.