waecmaths question:
A bag contains 5 red and 4 blue identical balls. If two balls are selected at random from the bag, one after the other, with replacement, find the probability that the is red and the second blue
Option A:
$\frac{2}{9}$
Option B:
$\frac{5}{18}$
Option C:
$\frac{20}{81}$
Option D:
$\frac{5}{9}$
waecmaths solution:
$\Pr (RB)=\frac{5}{9}\times \frac{4}{9}=\frac{20}{81}$
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