Question

Aubree recorded the grade-level and instrument of everyone in the middle school School of Rock below.

Seventh Grade Students
Instrument # of Students
Guitar 9
Bass 12
Drums 4
Keyboard 7
Eighth Grade Students
Instrument # of Students
Guitar 12
Bass 14
Drums 5
Keyboard 8

Based on these results, express the probability that a seventh grader chosen at random will play an instrument other than drums as a percent to the nearest whole number.

Answer 1

88%

Explanation:

probability of 7th grader playing other instruments apart from drum = total number of students not playing drum / population of the 7th grade class

total number of students not playing drum = 9 + 12 + 7 = 28

population of the 7th grade class = 28 + 4 = 32

28/32 = 0.875

to express in percentage multiply by 1000 = 87.5%

To round off to the nearest whole number, look at the first number after the decimal, if it is less than 5, add zero to the units term, If it is equal or greater than 5, add 1 to the units term.

88%