Mya wants to purchase a bicycle that costs $420. How many lawns will Mya have to mow, in total, in order to make enough money to pay for the bicycle?

Since we know that time and number of students vary inversely we can have a general formula of .  Rearrange the equation to solve for x to get .

In this case y = 16 and x = 3.  So that k = 16 * 3 and k = 48 then.

Now we can us the 48 in the original equation to get:

Plugging in 2 for x we get:
or C