Question

Two substances A (t1/2= 5 mins) and B
t1/2= 15 mins) follow first order kinetics are
taken in such a way that initially [A]= 4[B].
Calculate the time after which the concentration
of both the substance will be equal.
(1) 15 min (2) 20 min (3) 10 min (4) 25 min ​

Answer 1

25min

but I'm not sure...........

please follow me dear friend please