ShmoopTube

Where Monty Python meets your 10th grade teacher.

Search Thousands of Shmoop Videos


Elementary Probability Videos 5 videos

SAT Math 1.3 Statistics and Probability
276 Views

SAT Math 1.3 Statistics and Probability. Approximately what is the probability that they will be placed in alphabetical order?

SAT Math 1.4 Statistics and Probability
380 Views

SAT Math 1.4 Statistics and Probability. If two standard 6-sided dice are rolled, what is the probability that the sum of the dice will be gre...

SAT Math 1.5 Statistics and Probability
358 Views

SAT Math 1.5 Statistics and Probability. If Silas draws one card, then places it in his pocket and draws another, what is the probability that...

See All

SAT Math 3.2 Statistics and Probability 195 Views


Share It!


Description:

SAT Math 3.2 Statistics and Probability


Transcript

00:02

Here’s your shmoop du jour, brought to you by Marbles.

00:06

If found, please return to… oh, we can’t even remember where.

00:10

A bag contains yellow, blue, and red marbles.

00:13

The probability of drawing a red marble is 1/4 and the probability of drawing a yellow marble is 3/5.

00:19

If there are 100 marbles in the bag, how many are blue?

00:23

And here are the potential answers…

00:26

To solve this problem, we just have to figure out what fraction of marbles are blue.

00:31

Okay, we’re given the probability of drawing a red and yellow marble, so we can figure

00:35

out how many red and yellow marbles are in the bag.

00:37

We start with 100 marbles. 1/4 of them are red.

00:41

To find how many marbles that is, we just have to find 1/4 of 100.

00:44

That’s easy, multiply the two, and voila, that’s it.

00:47

25 marbles are red.

00:49

Now for yellow. The problem tells us that 3/5 of them are yellow.

00:54

Again, we multiply 3/5 times 100 and we get 60.

00:58

Since there are 25 red marbles and 60 yellow marbles and all the rest are blue....

01:04

...we get 25 plus 60 is 85.

01:08

Then, just subtract that 85 from 100, and we get 15 are blue.

01:12

So our answer is (B).

Related Videos

SAT Math 2.1 Geometry and Measurement
2779 Views

SAT Math 2.1 Geometry and Measurement. What is the measure of angle z in terms of x and y?

SAT Math 9.4 Algebra and Functions
1300 Views

SAT Math 9.4 Algebra and Functions

SAT Math 9.2 Algebra and Functions
377 Views

SAT Math 9.2 Algebra and Functions

SAT Math: Identifying an Equation for the Average of Two Percentages
23 Views

In 2014, the unemployment rate of one county in California was 7%. In another county, the unemployment rate was 11%. Which of the following express...

SAT Math: Which Equation Represents Profit?
13 Views

Angela is making cookies for a bake sale. She expects each batch of her cookies to sell for $40. It costs her $10 to make one batch of cookies, and...