IT Placement Practice Test 9

As the objects are replaced, the probability of drawing red or blue is equal.
Probability to draw exactly 3 red hats and 1 blue hat = 1/2 × 1/2 × 1/2 × 1/2 = 1/16.
Similarly probability to draw exactly 3 blue hats and 1 red hat = 1/2 × 1/2 × 1/2 × 1/2 = 1/16.
Total probability = 1/16 + 1/16 = 1/8.