Analysis and Approaches for IBDP Maths Ebook 1 | Page 271

Front Page
Exercise 87
1. A discrete random variable X has the following probability distribution.
x 4 8 12
P( X � x)
2
10k k
2
20k
(a) Find the value of k .
(b) Find P( X �12 | X � 6) .
[4]
[3]
2. A discrete random variable X has the following probability distribution.
x 12 24 30 36
P( X � x)
k
2
7k
2
8k k
(a) Find the value of k .
(b) Find P( X �24 | X � 20) .
3. A discrete random variable X has the following probability distribution.
x 7 14 21 28 35
P( X � x)
k 3k
2
10k
2
6k
2
5k
(a) Find the value of k .
(b) Find P( X �15 | X � 25) .
4. A discrete random variable X has the following probability distribution.
x 0 1 2 3 4 5
P( X � x)
2
k k
2
4k
2
8k 4k
2
k
(a) Find the value of k .
(b) Find P(2 � X � 4 |1� X � 4) .
[4]
[3]
[4]
[3]
[4]
[3]
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