5=1=100%
So now 9 In relation to the 5
9=more than 1=more than 100%
So if you divide out each of the 5 laps amongst the 100% each lap equals 20% of the 100%
So if each lap equals 20%
Each of the 9 laps also equals 20%
So 9times 20%= 180% which makes sense because he’s only one lap off trim double.
But it’s asking for the percent increase so you can do this a few ways
180-100=80
(9-5)times20=80
Good luck