Question

Kofi estimated that he would run a total of 10 km in 1 h. In 1 h, he actually ran 46 times around a track 0.25 km long, going a total distance of 11.5 km.
What was the percent error in Kofi’s estimate? Round to the nearest tenth of a percent, if necessary.


A.
1.5%

B.
5%

C.
13%

D.
23%

Answer 1

The equation to find percent error is

$\frac{actual-theoretical}{theoretical}*100$

where actual is the value that actually came out (in this case, 11.5 km) and theoretical is the value that was supposed to come out (in this case, 10 km).  Just plug in the numbers and simplify.

$\frac{actual-theoretical}{theoretical}*100\\\\\frac{11.5-10}{10}*100=\frac{1.5}{10}*100=15\%\ error$

So, the true answer would be 15%.  Apparently, the question you're asking takes 11.5 as the theoretical and the 10 as the actual (which I personally disagree with)

If you plugged in the numbers that way, the answer comes out to 13.04%.  So, the correct answer for your answer choices is c. 13%