Answer:
0.5
Step-by-step explanation:
Let D be the event of selecting a marble with dots.
Let P be the event of selecting a purple marble.
The probability of selecting a marble with dots, P(D)=0.2
The probability of selecting a marble that is both purple and has dots, 
We want to determine the probability of selecting a purple marble given that the marble has dots on it, P(P|D)
By the definition of conditional probability:

The probability of selecting a purple marble given that the marble has dots on it is 0.5.
Answer:
8
Step-by-step explanation:
The fact that DE is perpendicular to AC means triangles AED and CED are congruent and side AD is equal in length to side CD.
5x -20 = 2x +4
3x = 24 . . . . . . . add 20-2x
x = 8 . . . . . . . . . .divide by 3
The value of x is 8.
If both triangles are congruent (that's what the sign means), then AD=CB, and CD=AB. Substituting what we are given into CD=AB,
6x-5=3x+10
Solving the equation:
3x=15
x=5
So we know that 2x+4 (the value of AD) becomes 2*5 +4, and you get 14. Since we know that AD=CB, then CB is also 14. No need to find y!
Answer: CB=14
Negative exponents work like this:

So, you have

This number is less than 1, so she will play tennis.