Let A be concentration of chemical A and
B be concentration of chemical B

rate is proportional to A^2 / B

B is increased by 100% ie it is now 2B

A^2 must become 2*A^2
so A must become A*sqrt(2)
= 1.414 A

hence A should increase by 41.4 %


A request: If possible please type the question. Lot of us will be able to save some time. Thanks a lot.

i dont understand why A^2 should become 2A^2....
can you please explain the same...

thanks

hi
let first rate be R1 = A^2/B
let new concentration of A required be A' and new concentration of B be B'
Given, B'= 2B
therefore new rate, R2=A'^2/B'=A'^2/2B
For both the rates to be same, i.e R1=R2
A'^2/B=A^2/2B
A'^2=A^2/2
A'=A/square root of 2
increase % = (square root of 2 -1) *100 = 1.41-1 *100 =40%
therefore answer is 40%[/img]

good work !!!

thanks