Question

what is the range of 16.20, 15.50, 14.40, 16.30, 16.20, 15.40, 16.10, 16.10 and 15.30 mins

Answer 1

range = 16.30 - 14.40 = 1.90

answer 
range = 1.90

Answer 2

First we pull out 16.30 since it is the biggest and then take out 14.40 since it is the smallest 

So, we have to subtract the numbers that we took out
   Like: 

16.30   -   14.40 = 1.90  which can also look like this 16.30 - 14.40 = 1.9

Therefore your answer would have to be: 1.90 aka 1.9 

Good Luck!