. A box contains 10 balls, numbered 1 through 10 (so the balls are distinct). a. A ball is drawn from the box at random. Compute the probability that the number on the ball was 3, 4, or 5. b. A ball is chosen at random and then a second ball is chosen at random from the remaining nine balls. Find the probability that the numbers on the two selected balls differ by 2 or more. c. Three balls are chosen (with replacement). Find the probability that the sum of the numbers on the balls is even.

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batolisis batolisis · Answer 1 · 2020-09-18T17:00:38+02:00

Answer:

A) 0.30

B) 0.9

C) 0.4

Step-by-step explanation:

Number of balls = 10

A ) probability that a ball drawn at random is numbered 3,4 or 5

number on ball to be drawn = 3 i.e 3,4 or 5

total number of balls = 10

hence the probability = 3 / 10 = 0.30

B ) probability that number written on two different balls drawn at random differs by 2 or more

p( numbers differ by 1 ) = 9 * (1/10) * (1/9) = 0.1

p( numbers on two balls differ by 2 or more ) = 1 - p( numbers differ by 1 )

= 1 - 0.1 = 0.9

C ) Probabilty that the sum of the numbers on 3 balls chosen is even

even numbers = 5 which are ( 2,4,6,8,10 )

The even numbers that can be gotten by summation of three balls are

(4.6,8,10 ) = 4

hence the probability of picking three balls with replacement whose sum = even number will be

= 4 / 10 = 0.4