Question

ai mi recorded the grade - level and instrument of everyone in the middle school school of rock below.
seventh grade students

instrument	# of students
bass	12
drums	6
keyboard	11

eighth grade students

instrument	# of students
bass	15
drums	4
keyboard	14

based on these results, express the probability that a seventh grader chosen at random will play the guitar as a fraction in simplest form.
answer

Explanation:

Step1: Find total seventh - grade students

To find the total number of seventh - grade students, we sum up the number of students for each instrument in the seventh - grade table.
The number of students for guitar is 7, bass is 12, drums is 6, and keyboard is 11.
So the total number of seventh - grade students $=7 + 12+6 + 11=36$.

Step2: Calculate the probability

The probability that a randomly chosen seventh - grader plays the guitar is the number of seventh - grade guitar players divided by the total number of seventh - grade students.
The number of seventh - grade guitar players is 7, and the total number of seventh - grade students is 36.
So the probability $=\frac{7}{36}$. Since 7 and 36 have no common factors other than 1, the fraction is in its simplest form.

Answer:

$\frac{7}{36}$