31 I think I’m not sure may be wrong
Answer:
We are to find the error made by Sadie and then find the correct simplification.
The error Sadie made is that she wrote
as
instead of
.
The square root of
is
and so she could have further simplified.
The correct simplification is shown below:

First, you have to find the median, which is the number in the middle: 25
Then cut the data in half by the median, so your new data sets are
15,29,20
and
31,38,41
Now you find the median of both of those sets, which is 29 and 38.
The interquartile range is the difference between the numbers, so 38-29 = 9.