Use the following for question 7 and 8: If X is the proportion of persons who will respond to one kind of mail-order sol

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Use the following for question 7 and 8: If X is the proportion
of persons who will respond to one kind of mail-order solicitation,
Y is the proportions of persons who will respond to another kind of
mail-order solicitation, and the joint probability density of X and
Y is given by f(x,y)=(2x+8y)/5 for 0<x<1, 0<y<1.
1.Find the probability that at least 30 percent will respond to
the first kind of mail-order solicitation.
2.find the probability that at most 50 percent will respond to
the second kind of mail-order solicitation given that there has
been a 20 percent response to the first kind of mail-order
solicitation.