How to do this because i do not understand how to do it

24.52%



Work Shown:

Convert the time 7:45, which represents 7 min 45 sec, to seconds only
7:45 = (7 min) + (45 sec)
7:45 = (7*60 sec) + (45 sec)
7:45 = (420 sec) + (45 sec)
7:45 = (420+45) sec
7:45 = 465 sec

Do the same for 5:51
5:51 = (5 min) + (51 sec)
5:51 = (5*60 sec) + (51 sec)
5:51 = (300 sec) + (51 sec)
5:51 = (300+51) sec
5:51 = 351 sec

So the initial time is 465 seconds and it drops to 351 seconds
Subtract the values to find the amount dropped: 465-351 = 114

Divide that difference over the initial time: 114/465 = 0.24516

Move the decimal over 2 spots to the right to convert to a percentage: 0.24516 --> 24.516%

Then round to the nearest hundredth of a percent (2 decimal places) to go from 24.516% to 24.52% which is our final answer

So the reduction is roughly 24.52%
This means if you took 24.52% of the initial time and subtracted it off, then you'd get to about 351 seconds.