Question

A group of students conducted a survey to find out about the preferred mode of transportation to school among their classmates. They surveyed 200 students from their school. The results of the survey are as follows:

120 students preferred to walk to school.

25% of the students preferred to use bicycles.

10% of the students preferred to take the bus.

Remaining students preferred to be dropped off by car.

Based on the above information, answer the following questions:

(i) What is the probability that a randomly selected student does not prefer to walk to school?

(ii) Find the probability of a randomly selected student who prefers to walk or use a bicycle.

(iii)(A) (B) One day 50% of walking students decided to come by bicycle. What is the probability that a randomly selected student comes to school using a bicycle on that day?

OR

What is the probability that a randomly selected student prefers to be dropped off by car?

Answer 1

(i) Number of students who do not prefer to walk = 200 − 120 = 80

 P (selected student doesn’t prefer to walk) = 80/200 or 2/5

(ii) Total number of students who prefer to walk or use bicycle = 120 + 50 = 170

 P (selected student prefers to walk or use bicycle) = 170/200 or 17/20

(iii) (A) 50% of walking students who used bicycle = 60

 Number of students who already use bicycle = 50

 P (selected student uses bicycle) = 110/200 or 11/20

 OR

(B) Number of students who preferred to be dropped by car = 200 − (120 + 50 + 20) = 10 students

 P (selected student is dropped by car) = 10/200 or 1/20