You need to specify the experiment to get an answer. However, most experiments require qualitative data (descriptive, non-numerical data) and quantitative data (measured, numerical data).
Indium has 49 protons
mass number (# of neutrons and # of protons combined) is 115
115 - 49 = 66
66 neutrons
a)
26C5 -> 26 choices of 5 things
b)
15C1 × 11C4
c)
11C1 × 15C4
d)
11C2 × 15C2
e)
11C4
or
15C4
