A bag contains 45 marbles of various colors. Jon draws 60 times, each time replacing the marble before drawing again. He gets a total of 12 blue marbles.

Which is best prediction of how many blue marbles are in the bag?

A.
5

B.
9

C.
12

D.
15

Question

A bag contains 45 marbles of various colors. Jon draws 60 times, each time replacing the marble before drawing again. He gets a total of 12 blue marbles. 

Which is best prediction of how many blue marbles are in the bag?
	
	
 
A.
	5
	
 
B.
	9
	
 
C.
	12
	
 
D.
	15

anonymous · Answer

I would say a 60/12=5 idk though just what ithink

zarkon · Answer

let x= number of blue

the probability of blue is x/45

the expected value of blue is $\large {60\frac{x}{45}=x\frac{4}{3}}$

set equal to 12

$$x\frac{4}{3}=12$$

$$x=9$$