Question

A bag contains 9 9 w h i t e w h i t e marbles, 3 3 y e l l o w y e l l o w marbles, 7 7 b l u e b l u e marbles. If one marble is drawn from the bag then replaced, what is the probability of drawing a w h i t e w h i t e marble then a b l u e b l u e marble? In a number guessing game. You ask a person to guess a number from one 1 to 10. If the person makes a random guess, what is the probability their guess will be less than 5 5 ? A bag contains 3 3 r e d r e d marbles, 7 7 b l u e b l u e marbles, 9 9 y e l l o w y e l l o w marbles. If one marble is drawn from the bag but not replaced, what is the probability of drawing a r e d r e d marble then a y e l l o w y e l l o w marble? Add Work

Answer 1

(1) Probability = Favorable Outcomes / Total Outcomes

Total Number of Marbles = 9W + 3Y + 7B = 19

P(Drawing a White marble first) = 9/19

P(Drawing a Blue marble second after replacing the white marble) = 7/19

Therefore the required probability = 9/19 * 7/19 = 63 / 361 = 0.1745

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(2) Probability = Favorable Outcomes / Total Outcomes

Favorable Outcomes = A number less than 5 = 1, 2, 3 and 4 = 4 outcomes

Total Outcomes = 10 (any number from 1 to 10)

P(Choosing a number less than 5) = 4 / 10 = 0.4

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(3) Probability = Favorable Outcomes / Total Outcomes

Total Number of Marbles = 3R + 7B + 9Y = 19

P(Drawing a Red marble first) = 3/19

P(Drawing a Yellow marble second without replacing the red marble) = 9/18 = 1/2

Therefore the required probability = 3/19 * 1/2 = 3 / 38 = 0.0789

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