Answer:
b = 30 / a
which agrees with the third expression in the list of possible options
Step-by-step explanation:
When we say that a and b vary inversely, that means that in mathematical form:
b = k / a where "k" is the so called "constant of proportionality". In order to write the function that models this inverse variation, we need to find the value of "k". We do such by using the information they provide (b = 5/2 when a = 12):
5/2 = k / 12
Then, solving for "k":
5 * 12 / 2 = k
60 / 2 = k
k = 30
Then we can now write the function that models this inverse variation:
b = k / a
b = 30 / a
