VIJAYTHAPLIYAL wrote:

didn't get it... pls explain..?

I am using a weighted average formula , Since the question is asking for a final concentration of a mix that is the same as asking for the weighted average of the 2 solutions concentration of alcohol.

Weight A concentration of alcohol in B - Weighted average of the final mix

--------- = ------------------------------------------------------

weight B Weighted average of the final mix - Concentration of alcohol in A (given as 24%)

Question asks for the weighted average of alcohol concentration in the final mix? thus we need Weight A, Weight B , Concentration of alcohol in B

FROM 1

Weight A 1

--------- = --- We still need concentration of alcohol in B......... INSUFF

weight of B 4

FROM 2

Concentration in B = 1.5 *0.24............. INSUFF since we need Weight A and Weight B

Both together

we have all 3 missing unknowns to solve the equation.........thus suff

C