Callie has 5 yellow pencils 5 red pencils 1 white pencil and 4 pink pencils in her desk drawer. If she picks a pencil at random from her drawer, what is the probability that she will not pick a yellow one
A.1/3
B.2/3
C.4/15
D.3/5
B?
Billy has 4 red marbles 5 green marbles and 8 blue marbles in a bag. He reaches into the bag pulls out 1 blue marble and does not put it back into the bag. What is the probability that the next marble he pulls out of will be red
A.4/17
B.1/4
C.4/13
D.7/16
B?
Yes! Both are right.
To find the probability that Callie does not pick a yellow pencil, we need to determine the total number of pencils in her drawer and the number of yellow pencils in her drawer.
The total number of pencils in her drawer is the sum of the number of yellow, red, white, and pink pencils: 5 + 5 + 1 + 4 = 15.
The number of yellow pencils in her drawer is 5.
Therefore, the number of non-yellow pencils in her drawer is 15 - 5 = 10.
The probability of not picking a yellow pencil can be calculated by dividing the number of non-yellow pencils by the total number of pencils:
P(not picking a yellow pencil) = Non-yellow pencils / Total pencils
= 10 / 15
= 2/3
So, the correct answer is B. 2/3.
Now, let's find the probability that Billy will draw a red marble on the next draw after pulling out a blue marble without putting it back into the bag.
The total number of marbles in the bag after the first draw is 4 (red marbles) + 5 (green marbles) + 8 (blue marbles) - 1 (blue marble removed) = 16.
The number of red marbles in the bag after the first draw remains at 4.
Therefore, the number of non-red marbles in the bag is 16 - 4 = 12.
The probability of drawing a red marble on the next draw can be calculated by dividing the number of remaining red marbles by the total number of marbles:
P(drawing a red marble) = Remaining red marbles / Total marbles
= 4 / 16
= 1/4
So, the correct answer is B. 1/4.