The total number of variables in the equation 3a + b + 6ab = 0 is 3.
12
A variable is an unknown quantity whose value is not constant.
In the given equation 3a + b + 6ab = 0, "a" and "b" are the variables. "ab" is not considered as a separate variable because, if "a" and "b" are individually found, "ab" can be found. Hence, there are 2 variables in the equation and not 3.