Ineed on b. round each of the rainfall totals to the nearest tenth.

The tenth place is located where the '5' is in the following number: 2.54 
So, you look at the number after the 5 to see if you round it up or down.

Remember the basic rule of rounding - if the digit after the digit you are rounding is 5 or above, then you round the digit up by one. If the digit is 4 or below, then you leave that digit alone.

Let's look at the first one.
Rochester - 0.97 
The nine is in the tenths place, and the digit after it is greater than 5, so you round it up to 1.
Ithaca - 0.947
The digit after the nine is below five, so you don't round it up, leaving it at 0.9.
Saratoga Springs - 1.5
There is no digit after the 5, so you leave this one as 1.5.
New York City - 1.268
The digit after the 2 is greater than 5, so you round it up to 1.3.

I hope that I helped :)