Question

Zooey predicts the movie will be 90 minutes long. If the movie actually is 102 minutes long, what is Zooey's percent error? Round your answer to the nearest tenth of a percent.

Answer 1

102 - 90 = 12
12 / 102 = 0.1176 = 11.76 rounds to 11.8% <==

Answer 2

%error=100(prediction-actual)/actual

%error=100(90-102)/102

%error≈ -11.8%

Now the negative sign indicates that she underestimated the length of he movie by 11.8%, but technically the percent error is an absolute value so it is just 11.8% error.