Problem

In an ore containing uranium, the ratio of

{}^{238}\text{U}

{}^{206}\text{Pb}

nuclei is 3. Calculate the age of the ore, assuming that all the lead present in the ore is the final stable product of

{}^{238}\text{U}

. Take the half-life of

{}^{238}\text{U}

to be

4.5 \times 10^9

years..