Please help, unsure how to do this, in c#

Test 4 Consumable

public static int Test4(double onHand, double consume)

Given two doubles (onHand and consume) that represent the amount of an on-hand resource (onHand) and the amount of the resource that is consumed per cycles (think a time period). You are to determine how many cycles (time periods), before the on-hand amount is used up. For example, if you have 1 gallon of milk (onHand)and use 1 quart (1/4 gallon) per day (consume), determine when you expect to run out of milk (4 days). Return the number representing when the on-hand amount reaches 0 (or becomes negative). You may find it necessary to use the Round method from the Math class to avoid floating-point errors. I'd suggest rounding the results of each computation to 3 decimal places.