The number of hours, h, it takes for a block of ice to melt varies inversely as the temperature, t. If it takes 3 hours for a square inch of ice to melt at 60 degrees, find the constant of proportionality

Since the melting time h varies inversely with temperature t, h = k/t, where k is the constant of proportionality. Multiply both sides by t to get k = ht. Using h = 3 hours and t = 60 degrees gives k = 3 × 60 = 180, so the constant is 180 (choice B).

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