Two different solutions of alcohol with respective proportions of alcohol to water of 3:1 and 2:3 were combined. What is the concentration of alcohol in the new solution if the first solution was 4 times the amount of the second solution? Choose the correct option.
A) 62
B) 65
C) 68
D) 70
E) 72
SOL:   Lets assume that 40L of sol1 was mixed with 10L of sol2.   Alcohol in Sol1: 40*3/4 = 30L   Alcohol in Sol2: 10*2/5 = 4L   Total Alcohol in the mixed solution of 50L = 30 + 4= 
<gadget id="calculator">30 + 4</gadget>
<output>34</output>
34L   Alcohol concentration in the new sol: (34/50)*100= 
<gadget id="calculator">(34/50)*100</gadget>
<output>68</output>
68%   ANSWER:68
<result>C</result>
Two different solutions of alcohol with respective proportions of alcohol to water of 3:1 and 2:3 were combined. What is the concentration of alcohol in the new solution if the first solution was 4 times the amount of the second solution?