Answer:
It takes 2.32 more seconds to swim the second half.
Explanation:
If lily swims 100 meter and she swims the first half in 27.8 seconds and the second one in 30.12 seconds, we have that the distance for both sections is the same (50 meters) so we have to analyze the time.
If we called "x" the time of the first section and "y" the time for the second one, we can write y = x + c, where "c" is how much longer does it takes to swim the second half.
⇒ replacing with data given before:
30.12 seconds= 27.8 seconds + c ⇒
30.12 seconds - 27.8 seconds = c
⇒ c= 2.32 seconds.
Summarizing it takes 2.32 more seconds to swim the second half.