Answer:
Step-by-step explanation:
The total number of marbles is 20
Question A
P(Red) = 4/20 = 1/5
P(yellow) = 9/20
P(Red then Yellow) = 1/5 * 9/20 = 9 / 100
Question B
P(B) = 6/20
P(B again) = 5/19 because you have 1 less total plus 1 less blue.
P(B and B) = 6/20 * 5/19
P(B and B) = 30/ 380 = 3/38
A= 0.25 or 1/4
Hope this helps:)
A binomial squared is written like

So, we have 
So, we want to complete the square 
We can add and subtract 9 to write

Answer:
4:11
Step-by-step explanation:
let's say there 15 students, 10 of them study a language. Of the 10, 4 (the 2/5) study french, so of the 15 students 4 study french, making it 4:11.