She is incorrect cause if we take the number 20 and take 25% of it it equals 5 so now 20 is only 15. They if we take 75% away from 20 is equals 15 so then we only have 5 from 20 left. Therefore she’s incorrect because 75% leaves 5/20 and 25% leaves 15/20. Hope that makes sense.
perimeter = 2L +2W
the problem states the length ( L) is 2 meters longer then width, so L = w+2
so perimeter =2(w+2) +2w
24 = 2(w+2) +2w
24 = 2w+4 +2w
24 = 4w+4
20=4w
w=20/4 = 5