In a classroom there are 30 students. 1/3 of them are boys. Among the girls, 40% own dogs, 20% own a cat, and the rest have no pets. How many girls in the class have no pet?
2/3 students are girls because 1 - (1/3) = 2/3
20 students are girls because 30 x (2/3) = 
<gadget id="calculator">30*(2/3)</gadget>
<output>20</output>
20
40% of the girls don't have any pets because 100 - 40 - 20 = 
<gadget id="calculator">100-40-20</gadget>
<output>40</output>
40
8 girls in class have no pets because 20 x .4 = 
<gadget id="calculator">20*.4</gadget>
<output>8</output>
8.

<result>8</result>