Answer :
Percent error is:
(What you got - what you should have got) * 100 / what you should have got
So in this case:
(25-27) * 100 / 27 = 7.407 with the (.407) repeating
(What you got - what you should have got) * 100 / what you should have got
So in this case:
(25-27) * 100 / 27 = 7.407 with the (.407) repeating