Question

There are 120 students in a school. In a survey of all students, 47 students support delaying the start of school, 53 students do not support delaying the start of school, and 20 students are indifferent to the school start time. If a student is selected at random, find the probability that the selected student is not indifferent to the school start time. Express your answer in simplified rational form.

Answer 1

The probability that the selected student is not indifferent to the school start time is 0.8333.

Explanation:

Define the events s follows:

X = students support delaying the start of school

Y = students do not support delaying the start of school

Z = students are indifferent to the school start time.

The events X, Y and Z are mutually exclusive events.

That is they cannot occur together.

Compute the probability that the selected student is not indifferent to the school start time as follows:

P (Z') = P (X or Y)

= P (X) + P (Y)

`=(47)/(120)+(53)/(120)\\\\=(47+53)/(120)\\\\=0.8333`

Thus, the probability that the selected student is not indifferent to the school start time is 0.8333.