I am going to eliminate zeros from this to make it easier.

Ed…..680
Ann…450
Bob…360
Dot…210
Cal…190

You know the median is going to be the middle number because there are 5 people.

We know Cal’s sales are still less than Ann’s sales after they fix the error

We know the median after fixing the error is 330

The only way for the median to be 330 is if Ann or Bob have 330 total sales.

Bob at 330:
It would take 140 from Ann’s to make Cal’s 330. However, this would leave ann with 310 which would be less than Cal’s. Therefore, this is not possible.

Ann at 330:
It would take 120 away from Ann. Ann would have 330 and Cal would have 310.
This satisfies the criteria of the problem.

The answer would be 120. Hope this helps!

Thx Dmateer25. Since I got this question from some document, I have no way or verifying the correct answer.

arranging the sales in increasing order

C- 190
D - 310
B - 360
A - 450
E - 680

Median - 360

Median changes to 330.

Only C and As sales figure change rest all remain same. Also A>C

This means either C is the new median or A

C can't be the new median since then C>A
Hence A is the new median, its value = 330
Change - 450 - 330. = 120.

One more vote for D)

It has to be 120 or 140 so that the median is 330(odd count of numbers) i.e 190+140 or 450-120

Since its given Cal's sale even after taking this misrecorded sale from his total is greater than Bob's it has to be 120 subtracted from 450 making the median 330

Cal - 330
Bob - 310