For a chemical reaction $\mathrm{A}+\mathrm{B}\to$ Product, the order is 1 with respect to A and B.

Rate mol L-1 S-1	[A] mol L-1	[B] mol L-1
0.10	20	0.5
0.40	x	0.5
0.80	40	y

What is the value of x and y?

Given order is one with respect the both A & B, then as rate is increased four times when conc of B is   then conc of ‘A’ increases by four times. ${\text{x=80\hspace{0.17em}mol\hspace{0.17em}lt}}^{-}$as conc of A becomes half, but rate is doubled means, rate change is four times w.r.to B. That means B conc increases by four times