Answer:

Explanation:
You have that x varies directly with p*m (which means that if the result of m*p increase, x increase)
And you have too that x is inversely with y (which means that if y increase, x decrease).
Then you must get:

If the problem says that x is 2, y is 4, p is 0.5, and m is 2
the constant value should be 8, in this way:

If you replace:

The result is x=2