Question

On Tuesday, 3/8 of the students wore blue shirts and 1/12 of the students wore white shirts. What fraction of students wore either a blue shirt or a white shirt?

Answer 1

$\bf \stackrel{\textit{blue shirts}}{\cfrac{3}{8}}+\stackrel{\textit{white shirts}}{\cfrac{1}{12}}\impliedby \textit{we'll use an LCD of 24} \\\\\\ \cfrac{(3\cdot 3)~+~(2\cdot 1)}{24}\implies \cfrac{9+2}{24}\implies \cfrac{11}{24}$

Answer 2

11
---    of students wore either a blue or white shirt. This is because if you add 
24       

3     1
-- + --- , that is what you get. You do this by finding the common multiple of 
 8    12
   
             the two denominators (which is 96). So you do 8     36  , and get  44,
                                                                                          --- + ----                   ---
                                                                                        96       96                   96
which then simplifies to your answer, which is  11 . Hope this helps! :)
                                                                          ----
                                                                          24
(It can also be written as 11/24).