Chemical Kinetics: JEE Main 2021 Chemistry question

For the first order reaction A $\to$ 2B, 1 mole of reactant A gives 0.2 moles of B after 100 minutes. The half life of the reaction is __________ min. (Round off to the nearest integer). [Use : ln 2 = 0.69, ln 10 = 2.3] Properties of logarithms : ln x^y = y ln x; $\ln \left( {{x \over y}} \right) = \ln x - \ln y$ (Round off to the nearest integer)