Here, there are two types of questions, True/False or Multiple Choice Questions (T/F or MCQ), and each of them are divided into Easy and Difficult type, as shown below in the tree diagram.So, in all, there are,500 T/F questions and 900 MCQs.Also, there are 800 Easy questions and 600 difficult questions.⇒ the sample space of this experiment has 500+900=1400 outcomes.Now, let E be the event of 'getting an Easy question' andF be the event of 'getting an MCQ′ ⇒P(E)=1400800​=148​ And P(F)=1400900​=149​ Now, E∩F is the event of getting an MCQ which is Easy.Clearly, from the diagram, we know that there are 500 MCQs that are easy. So P(E∩F)=1400500​=145​……… (ii)  Now, we know that by definition of conditional probability,​P(E∣F)=P(F)P(E∩F)​⇒P(E∣F)=9/145/14​=95​[ Using (i) and (ii)] ⇒P(E∣F)=95​​