To find out how many students voluteered, simply add the fractions:
[tex] \dfrac{1}{3}+\dfrac{1}{4}+\dfrac{2}{6} [/tex]
Remember that 2/6=1/3, so the sum is actually
[tex] \dfrac{1}{3}+\dfrac{1}{4}+\dfrac{1}{3} [/tex]
We can sum the first and last terms immediately:
[tex] \dfrac{2}{3}+\dfrac{1}{4}[/tex]
And finally, we can change both fractions so that they have the same denominator:
[tex] \dfrac{2}{3}+\dfrac{1}{4} = \dfrac{8}{12}+\dfrac{3}{12} = \dfrac{11}{12}[/tex]
