After the 3rd pick we have: 4 white, 3 red and 8 black marbles.
The probability that the 4th marble is black is:
P ( Black ) = 8 / 15 = 0.5333
After the 4th pick we have: 4 white, 3 red and 7 black marbles.
P ( Red or Black ) = 10 / 14 = 5 / 7 = 0.7143
Since opposite angles of a cyclic quadrilateral are supplementary,
A= 180-101=79°
B= 180-68=112°
-4.75= z/2
Multiply both sides by 2
-4.75(2)= z/2(2)
Cross out 2 and 2, divide by 1 and becomes z
z=-9.5
Answer: z= -9.5
I hate study island lol and are those supposed to be powers? Like 3 to the power of 8