A survey of 100 students in an institution shows that 80 students speak Hausa and 20 students speak Igbo, while only 9 students speak both language. How many students speak neither Hausa nor Igbo?
A
0
B
9
C
11
D
20
Verified Correct Answer: B.
Step-by-Step Mathematical Solution
Let the number of students that speak Hausa and Igbo be represented by H and I respectively.
n(H only) = 80 - 9 = 71.
n(I only) = 20 - 9 = 11.
n(neither H nor I) = 100 - (71 + 9 + 11)
= 100 - 91 = 9 students.
Source: Myschool Past Questions Archive (Record #30798)