eureka this is a q from kinetics
just make a rxn A reversibly gives b type and write the rate of formation of B (net rate ) and solve it like first order eq and express it in form of x (x=B form) and finally put the value of x as it is half the value of B at eq
after doing it your formulae will be
T= ln2/(K1+K2)
now put the values of K1 and K2
NB on first look the formulae looks wrong as K1 and K2 should not be adding up as the more the value of K2 the half life should be more but by the formulae it is less why?? do check out yourself