What is the range for the following set of measurements? 3.1 ml, 2.7 ml, 4.6 ml, 1.9 ml, 8.7 ml

The answer would be 6.8mL. 

Range is defined as the difference between the lowest and highest value. So based on the data given, the lowest value is 1.9mL and the highest is 8.7mL. All you need to do is subtract:

       8.7mL         -         1.9mL      =     6.8mL
(Highest value)        (Lowest value) 

The range is then 6.8mL.

Iwould say silver and gold