Probability - Jamb Mathematics Past Questions and Answers

Question 36:

• JAMB 1993

A number is selected at random between 20 and 30, both numbers inclusive. Find the probability that the number is a prime

A. \(\frac{2}{11}\)
B. \(\frac{5}{11}\)
C. \(\frac{6}{11}\)
D. \(\frac{8}{11}\)

Question 37:

• JAMB 1993

The chances of three independent events X, Y, Z occurring are \(\frac{1}{2}\), \(\frac{2}{3}\), \(\frac{1}{4}\) respectively. What are the chances of Y and Z only occurring?

A. \(\frac{1}{8}\)
B. \(\frac{1}{24}\)
C. \(\frac{1}{12}\)
D. \(\frac{1}{4}\)

Question 38:

• JAMB 1994

\(\begin{array}{c|c} \text{Age in years} & 10 & 11 & 12 \\ \hline \text{Number of pupils} & 6 & 27 & 7\end{array}\)
The table above shows the number of pupils in each age group in a class. What is the probability that a pupil chosen at random is at least 11 years old?

A. \(\frac{27}{40}\)
B. \(\frac{17}{20}\)
C. \(\frac{33}{40}\)
D. \(\frac{3}{20}\)

Question 39:

• JAMB 1994

In a survey, it was observed that 20 students read newspapers and 35 read novels. If 40 of the students read either newspapers or novels, what is the probability of the students who read both newspapers and novels?

A. \(\frac{1}{2}\)
B. \(\frac{2}{3}\)
C. \(\frac{3}{8}\)
D. \(\frac{3}{11}\)

Question 40:

• JAMB 1995

Let p be a probability function on set S, where S = (a₁, a₂, a₃, a₄). Find P(a₁) if P(a₂) = \(\frac{1}{3}\), p(a₃) = \(\frac{1}{6}\) and p(a₄) = \(\frac{1}{5}\)

A. \(\frac{7}{3}\)
B. \(\frac{2}{3}\)
C. \(\frac{1}{3}\)
D. \(\frac{3}{10}\)