BTGmoderatorDC wrote:After each throw of a red die, the face that shows is marked with a blue stripe. What is the probability that after 6 throws all faces of the die will be marked blue?
A. 3/126
B. 5/324
C. 4/216
D. 4/182
E. 5/216
1. First throw: Since all the six faces are red, any face would do; so the probability = 6/6 = 1
2. Second throw: Since one face is blue and five are red, and we need any of the five faces, the probability = 5/6
3. Third throw: Since the two faces are blue and four are red, and we need any of the four faces, the probability = 4/6
4. Fourth throw: Since the three faces are blue and three are red, and we need any of the three faces, the probability = 3/6
5. Fifth throw: Since the four faces are blue and two are red, and we need any of the two faces, the probability = 2/6
6. Sixth throw: Since the five faces are blue and only one is red, and we need that one red face, the probability = 1/6
Combined probability = 1*5/6*4/6*3/6*2/6*1/6 = 5/324
The correct answer:
B
Hope this helps!
-Jay
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