Can someone please help me, I’ve hit a bit of a road block with this. 

I have a list made up of integers that is constantly changing in size and value, and I would like to select one of these integers using zl.nth  so that I can scale it up or down, and then reinsert it back into the list in the same position. 

Here is an example. Let’s say the list consists of 1 24 6 9 74. I would like to select the 2nd number in the list which is 24 and scale it up to 48, so that the list becomes 1 48 6 9 74. Keep in mind that the list is a changing variable, as well as the scale value, and that I require numbers to be selected from the list based on their position rather than their numeric value.

Can anyone suggest how i could do this?