Casho recorded the grade-level and instrument of everyone in the middle school School of Rock below. Seventh Grade Students Eighth Grade Students Instrument # of Students Instrument of Students Guitar 5 Guitar 9 Bass 10 10 Bass Drums Drums10 13 Keyboard 4 Keyboard 13 Based on these results , express the probability that an eighth grader chosen at random will play an instrument other than drums as a fraction in simplest form
First, we need to determine the total number of eighth grade students who play an instrument other than drums.
In the eighth grade, there are:
- 9 students who play guitar
- 10 students who play bass
- 13 students who play keyboard
Total number of eighth grade students who play an instrument other than drums = 9 + 10 + 13 = 32
Total number of eighth grade students = 9 (guitar) + 10 (bass) + 13 (drums) + 4 (keyboard) = 36
Therefore, the probability that an eighth grader chosen at random will play an instrument other than drums is:
32 (number of 8th grade students who play an instrument other than drums) / 36 (total number of 8th grade students) = 8/9
Therefore, the probability is 8/9.