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Answer:
4. n = 4
5. P(A|B) = 0.75
Step-by-step explanation:
4. The coefficient of x will depend on n. The expansion is ...
(5 +nx)^2(1 +3/5x)^n = (25 +10nx +n^2·x^2)(1 +3/5nx +...)
So, the x-term of the expansion is ...
25(3/5nx) +(10nx)(1) = 25nx
The problem statement tells us that is 100x, so we have ...
25nx = 100x
n = 100x/(25x) = 4 . . . . . divide by the coefficient of n
The value of n is 4.
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5. For the conditional probability formula, we need to know P(A∩B).
P(A∩B) = P(A) +P(B) -P(A∪B)
P(A∩B) = 0.5 +0.4 -0.6 = 0.3
Then the conditional probability is ...
P(A|B) = P(A∩B)/P(B) = 0.3/0.4
P(A|B) = 0.75
