The answer to the equation is 51.0%
C=2pi r
C = 2 pi 7
C= 14 pi
C= 43.96 in
3*4*3-2*4^2 = 36-32 = 4
hope helped
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
