To find the probability of a randomly choosen student listing oats as its favorite grain, divide the number of students that chose oats by the total number of students and multiply the fraction by 100%.
To find the total number of students, add the numbers under each cereal:
[tex]12+14+8+6=40[/tex]The number of students who chose oats, is 14. Then, the requested probability, is:
[tex]\frac{14}{40}\times100=35\text{ \%}[/tex]