Question

65=91/? What is the question mark

Answer 1

I would write the missing variable as x. It's what everyone uses.
Anyway, 91 divided by x is 65.
The way we can do this is reverse 65 and x.
91 divided by 65 = x.

91 divided by 1.4 = 65
65 x 1.4 = 91

x (or ?) = 1.4