Q2 in pic!
Ans: 2080

Dear Student
Important point :Elementary (single-step) reactions have reaction orders equal to the stoichiometric coefficients for each reactant.
So here order of the reaction with respect to A  is 1 and with respect to B is 2 
t_1/2 is proportional to 1/[P]^n-1 so here t_1/2 can be written as $\frac{k}{{\left[A\right]}^0{\left[B\right]}^1}$=$\frac{k}{\left[B\right]}$
if we compare exp no. 1 and 2 we see that in both concentration of A is equal and concentration of B is getting doubled which means that t_/2 will get halved =40/2 =20 min
xy=20 min

if we compare 3rd and 4th experiment then we see that concentration of B is halved that means that the half life will get doubled whic will be equal to 40 min
vz=40 min
Regards