Chemistry - Chemical Kinetics Question with Solution | TestHub

During the nuclear explosion, one of the products is${}_{\text{90}}\text{Sr}$with half life of$\text{6}\text{.93}$years. If$\text{1 }\text{μ}\text{g}$of${}_{\text{90}}\text{Sr}$was absorbed in the bones of a newly born baby in place of$\text{Ca}$, how much time (in years) is required to reduce it by$\text{90\%,}$if it is not lost metabolically?
Report your answer by rounding it up to a nearest whole number.