A certain lab experiments with white and brown mice only. In one experiment, 2/3 of the mice are white. If there are 7 brown mice in the experiment, how many mice in total are in the experiment?  Choose the most appropriate option: A) 39 B) 33 C) 26 D) 21 E) 10
Let total number of mice = M   Number of white mice = 2/3 M   Number of brown mice = 1/3 M = 7   =&gt; M = 21   Answer 21
<result>D</result>
A certain lab experiments with white and brown mice only. In one experiment, 2/3 of the mice are white. If there are 7 brown mice in the experiment, how many mice in total are in the experiment?