Thread: media word problem

Each number on a list containing 100 numbers is divided by 10 to produce a second list containing 100 numbers. Each of the 100 numbers on the second list is decreased by 2 to produce a third list of 100 numbers. The median of the third list is x. What would be the median of the original list (in expression form)?

How do you deduce that it would be: 10(x+2) ??

Explain your process. That is correct, but you still want to explain how you came up with this. And I thought this was a question about CNN, FOX News and MSNBC.

I'm not sure how to solve it--the answer is just the one supplied in m book

Originally Posted by harold

I'm not sure how to solve it--the answer is just the one supplied in m book

You are just performing linear transformations on the values in your sample space. For example - if you surveyed a group of kids when they were in middle school, and recorded their ages, if you wanted to interview them again 10 years later, all you would need to do is adjust each value by +10. Likewise the mean would be adjusted by +10 as well (the variation wouldn't change - see if you can suss out why).

This is no different. So, lets say you start with one list, whose median is Y. You are told that you are dividing all values by 10 to create a second list; if you di:



Then, you are decreasing all values by 2 to create the third list. And so you must also subtract the median by 2:



That is then equal to X, the median of the third list:



Now, how would you go about solving for Y, the median of the first list in terms of X?

Got it, thanks a bunch!