Question

Keenan places 3 green marbles, 4 yellow marbles and 1 blue marble in a bag.

Keenan then adds 1 green marble and 1 yellow marble to the bag.
Does the probability that Keenan will randomly choose a yellow marble increase, decrease or stay the
same?
Circle one:
Increases
Decreases
Stays the same
Justify your answer.

Answer 1

Stayed the same

Explanation:

Altogether, there are 8 marbles in the bag (before Keenan adds the other marbles.) The probability so far that he draws a yellow marble is 4/8, or 1/2.

When he adds the marbles to the bag, there are 10 marbles altogether and 5 yellow marbles. The probability now is 5/10, or 1/2.

The probability has stayed the same.

Answer 2

Explanation:

Beginning

Beginning total = 3 + 4 + 1 = 8

Beginning probability 4/8 = 1/2

Answer: So P(yellow) = 1/2

New Conditions

4 + 5 + 1 = 10

P(y) = 5/10 = 1/2

Answer: Stays the same