Find mean, median and mode of 140, 130, 90, 80, 60, 50, 30, 20, 10, 0

For the mean you would have to add up all the numbers up and divide by the amount of numbers. For your problem you would get 610/10= 61. 

For the median you would arrange all the numbers in order from least to greatest and cancel one from the left and one from the right each time. Since there is no middle number, the closest would be 50 and 60. Thus you you add 50+60 and get 110 and then divide by 2 giving you 55.

For the mode, there is no mode because none of the numbers repeat more than once.

I hope this clarifies your doubt. :)