Vir calculates that an object will take 2.3 seconds to fall to the ground. when vir times the object falling, it takes 2.5 seconds. what is vir's percent error ?

His percent error was by .2 of a second, so we can do  to get our answer. After dividing, you should have got around .0869. You can convert this to a decimal by moving the decimal spot 2 places to the right to get 8%.
8% is your answer.