In a certain large college, 22% of students own a car.
- (a)3 students from the college are chosen at random. Find the probability that all 3 students own a car.[1]
- (b)16 students from the college are chosen at random. Find the probability that the number of these students who own a car is at least 2 and at most 4.[3]
Mark scheme
Marking points from the official mark scheme (May/June 2020). The mark or mark type is shown in brackets.
- [B1] 0.22^3 = 0.0106
- [M1] P(2, 3, 4) = 16C2 0.22^2 0.78^14 + 16C3 0.22^3 0.78^13 + 16C4 0.22^4 0.78^12
- [A1] 0.179205+0.235877+0.216221
- [A1] 0.631
Write your answer and get it marked
On Oracle Prep you can write or photograph your own answer and have it marked by AI against this mark scheme, with feedback on what you missed.
Sign up free →