For the first order reaction A → B the half life is 30   min . The time taken for 75 % completion…

For the first order reaction $\mathrm{A}\to \mathrm{B}$  the half life is $30 \min$. The time taken for $75\%$ completion of the reaction is mm. (Nearest integer)

Given : $\log 2=0.3010$

$\log 3=0.4771$

$\log 5=0.6989$