Answer: a) 35%, b) 65%.
Step-by-step explanation:
Since we have given that
Probability of students speak Arabic = 0.25
Probability of students speak Chinese = 0.20
Probability of students speak both language = 0.10
Let A be the event for Arabic.
Let C be the event for Chinese.
a. What is the probability that the student can speak Chinese or Arabic?
[tex]P(A\cup B)=P(A)+P(B)-P(A\cap B)\\\\P(A\cup B)=0.25+0.20-0.10\\\\P(A\cup B)=0.35=35\%[/tex]
b. What is the probability that the student cannot speak either Chinese or Arabic?
[tex]P(A\cup B)'=100-35=65\%[/tex]
Hence, a) 35%, b) 65%.