Khan/khan-exercises — Issue #12970: Adding and subtracting decimals word problems - Question should specify correct units for the answer
Author: KhanBugz
Created: 2012-02-03 03:03:17+00:00
State: open
Labels: lion, safari, wrong-or-unclear

Reporter: andrew@avit.ca

The question of finding the difference between two runners' speed ("how much faster") gives enough information to be (mis-)interpreted as:

a percentage: 44% faster
a speed: 4.25 m/s faster
a time: 9.68 seconds faster

The only clue given is that the exercise is called "adding and subtracting" so I can just assume the answer should be in seconds. The question would be clearer if asked as "By how many seconds did Christopher beat Umaima?".

The word "faster" also looks like it's asking for the speed.

[adding_and_subtracting_decimals_word_problems.html?seed=166&problem=1](http://sandcastle.khanacademy.org/media/castles/Khan:master/exercises/adding_and_subtracting_decimals_word_problems.html?seed=166&problem=1&debug)

[Answer timeline](http://sandcastle.khanacademy.org/media/castles/Khan:master/exercises/adding_and_subtracting_decimals_word_problems.html?seed=166&problem=1&debug&activity=%5B%5D)

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