Which is steeper, 1/3 or 1/t

Assuming you are referring to the slope of lines, 1/3 would be steeper and you can also verify this by going to https://www.desmos.com/calculator/ica0tezl0j 

where you can see that the 1/3 line is steeper.

Line with slope 1/3, or slope 1/5?

 

For slope of 1/3, you go right 3 every 1 you go up: 1x/3 = y, x = 3y

 

Similarly, 1/5 is 5 for every 1.

 

Now, you see, the greater the slope, the steeper it is.

 

1/3 > 1/5

 

Thus, 1/3 is steeper.