Latanya recorded the grade-level and instrument of everyone in the middle school School of Rock below.
Seventh Grade Students
Instrument # of Students
Guitar 2
Bass 2
Drums 11
Keyboard 15
Eighth Grade Students
Instrument # of Students
Guitar 6
Bass 15
Drums 10
Keyboard 9
Based on these results, express the probability that an eighth grader chosen at random will play the keyboard as a fraction in simplest form.
The total number of eighth grade students is 40 (6 + 15 + 10 + 9). The number of eighth grade students who play the keyboard is 9.
Therefore, the probability that an eighth grader chosen at random will play the keyboard is 9/40. This fraction is already in simplest form.