Solution: An old asteroid is found. A rock from it yields 1.84 g of  238U92 and 4.22 g of  206Pb82. The molar mass of 206Pb82 is 205.974 g/mol, the molar mass of  238U92 is 238.029 g/mol, and the half-life of  

An old asteroid is found. A rock from it yields 1.84 g of  ²³⁸U₉₂ and 4.22 g of  ²⁰⁶Pb₈₂. The molar mass of ²⁰⁶Pb₈₂ is 205.974 g/mol, the molar mass of  ²³⁸U₉₂ is 238.029 g/mol, and the half-life of  ²³⁸U₉₂ is 4.46 x 10⁹ years. 

How old is this asteroid? Express your answer with the appropriate units.