A sample of Uraninite, a Uranium containing mineral was found on analysis to contain `0.214` gm of `Pb^(206)` for every gram of Uranium. Assuming that the lead all resulted from the radioactive disintegration of the Uranium since the geological formation of the Uraninite and all isotopes of Uranium other than`""^( 238)U` can be neglected. Estimate the day when the mineral was formed in the Earth's crust.
`[t_(1//2) " of " ^(238)U = 4.5 xx 10^(9)" years " ]`

Answer

`1.4 xx 10^(9)` yrs