6 c.c. of a 20% solution of alcohol in water is mixed with 4 c.c. of a 60% solution of alcohol in water. The alcoholic strength of the mixture is?

A. 20%

B. 26%

C. 36%

D. 40%

Answer: Option C

Solution(By Examveda Team)

Quantity of alcohol in 10 c.c. solution
= (20% of 6 + 60% of 4) c.c.
= $$\left( {\frac{{20}}{{100}} \times 6 + \frac{{60}}{{100}} \times 4} \right)$$    c.c.
= (1.2 + 2.4) c.c.
= 3.6 c.c.
∴ Required strength :
$$\eqalign{ & = \left( {\frac{{3.6}}{{10}} \times 100} \right)\% \cr & = 36\% \cr} $$