On Friday, Kaitlyn went to the park to work out. She started with a slow jog at a constant rate for five minutes. She then increased her speed to a faster, constant pace for seven minutes. She took a three-minute break, then ran for another 7.5 minutes at a constant pace to finish her two-mile run. She rested for the remainder of the time. During what domain interval will she reach 1.25 miles?
(1 point)
Responses
22.5≤s≤25
22.5 less-than-or-equal-to s less-than-or-equal-to 25
12≤s≤15
12 less-than-or-equal-to s less-than-or-equal-to 15
15≤s≤22.5
15 less-than-or-equal-to s less-than-or-equal-to 22.5
5≤s<12
5 less-than-or-equal-to s less than 12
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To find the domain interval during which Kaitlyn will reach 1.25 miles, we need to calculate the time it takes for her to run 1.25 miles and then determine the corresponding time interval.
Kaitlyn runs at a slower pace for 5 minutes and then at a faster pace for 7 minutes, which totals to 12 minutes already.
To find out how long it takes her to run 1 mile, we need to divide the distance by the time: 1.25 miles / 12 minutes = 0.1041667 miles/minute.
Since the two-mile run is split into two parts, we only need to consider the faster pace interval. Kaitlyn runs at a constant pace for 7.5 minutes during the second part of her run.
To find the distance covered during this interval, we multiply the pace (0.1041667 miles/minute) by the time (7.5 minutes): 0.1041667 miles/minute * 7.5 minutes = 0.78125 miles.
Since 1.25 miles is greater than 0.78125 miles, she will not reach 1.25 miles during the second interval.
Therefore, the correct answer is 5≤s<12, which means that it takes Kaitlyn between 5 and 12 minutes to reach 1.25 miles during her workout.