For the reaction  $\mathrm{A}+2\mathrm{B}\to {\mathrm{AB}}_2$, the experimental data is given as

Experiment	[A] in M	[B] in M	Rate in M/min
I)	0.025	0.025	0.0005
II)	0.05	0.025	0.0005
III)	0.075	0.05	0.002
IV)	0.1	0.075	0.0045

Order of the reaction is

Comparing experiment-I and II, 
Order w.r.t 
A [A] doubled, [B] remained constant and rate remained constant
2^x = 1
2^x = 2° ; x = 0
Comparing experiment I and IV Order w.r.t B 
[A] qudrapled, [B] tripled and rate increased by 9 times
$\begin{array}{rr}{4}^{\mathrm{x}}\cdot 3^{\mathrm{y}}=9;\text{ but }\mathrm{x}=0;\therefore 3^{\mathrm{y}}=9,\mathrm{y}=2,\mathrm{hence} & \\ \therefore \text{ rate }=\mathrm{K}\left[\mathrm{A}{]}^0\right[\mathrm{B}{]}^{2}2& \end{array}$