An Isotope of Thorium ${ } ^ { 227 } \mathrm { Th }$

question 220

Short Answer

An isotope of thorium, ${ } ^ { 227 } \mathrm { Th }$ , has a half-life of 18.4 days. How long will it take for 77% of the sample to decompose?
Please round the answer to the nearest tenth.