Please help, I will give brainliest.

Suppose that a and b vary inversely and that b=5/2 when a=12. Write a function that models the inverse variation.

b = 15/2a
b = 5/2a
b = 30/a
b = 5/24a

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

56

step-by-step explanation: