Kurt has a jar of marbles. six of the marbles are blue. the probability of randomly drawing a blue marble is 1/5. when kurt adds more blue marbles to the jar, the probability of drawing a blue marble becomes 1/4. how man blue marbles did kurt add to the jar?a) 1 b) 2 c) 3 d) 4

Remark

Interesting question. One out every 5 marbles is blue. If you have 6 marbles in there then the fraction is 6/x. Your first step is to solve for x. Then you dilute the contents of the jar by adding a new number (x) of marbles and the probability becomes 1/4.

Step One

Find the number of marbles before any more were added.

1/5 = 6/x Cross multiply

x = 30 So there were 30 marbles to start with.

Step Two

Now he adds x marbles to both the blue and the total and the probability becomes 1/4. Set that up

4(x + 6) = x + 30 Remove the brackets.

4x + 24 = x + 30 Subtract 24 from both sides.

4x = x + 30 - 24

4x = x + 6 Subtract x from both sides.

4x - x = 6

3x = 6 Divide by 3

x = 6/3

x = 2

Answer

He added 2 blue marbles. Note that you don't have to know anything about the rest of the marbles, except that they are not blue.

both graphs increase on their domain

neither graph has a y-intercept

step-by-step explanation:

the following points can be visualized easily from the graph

$6.42

step-by-step explanation: