Two-thirds of the class have brown eyes. Half of the students with brown eyes have black hair. If there are 6 students in the class with brown eyes and black hair, how many students are there in total?
There are 6 * 2 = 
<gadget id="calculator">6*2</gadget>
<output>12</output>
12 students with brown eyes and hair of any color.
There are 12 * 3/2 = 
<gadget id="calculator">12*3/2</gadget>
<output>18</output>
18 students in total.

<result>18</result>