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**Tweety** The random variable X~B( 50, 0.40). Find

a) the largest value of k, such that $\displaystyle P(X\leq k)< 0.05 $

B)the smallest number r, such that P(X>r) <0.01

I have done part 'a', by simply looking at the tables, n=50, p=0.40 and looking for the value for X that gives a probability less than 0.05. Which is k=13.

But I am stuck on part 'b', because it asks for x>r, and the tables only give values for $\displaystyle P(X\leq x ) $

Can someone show me how to work this out?

Thanks.