(d) normal energy of reactants two substances a and b are present such that [a] = 4 [b] and half life of a is 5 minute and of b1s 15 minute. if they s

(D) Normal energy of reactants Two substances A and B are present such that [A] = 4 [B] and half life of A is 5 minute and of B1s 15 minute. If they start decaying at the same time following first order, how much time later will the concentration of both of them would be same? (A) 15 minute (B) 9 minute (C) (D) 12 minute 6 minutee