The Bedrock in Hudson Bay, Canada is the oldest known rock bed on the planet. Using uranium/lead radiometric dating, it has been found to be 4.28 billion years old. If we assume that the rock only contained ²³⁶U in the beginning, what would be the mass of ²⁰⁶Pb in a sample of the rock if it currently contains 1.500 g of ²³⁶U? (The half-life of  ²³⁶U is t_1/2 = 4.47 x 10⁹ years.)