There are 20 black cell phones and 30 white cell phones in a store. An employee takes 10 phones at random. Find the probability that A. there will be exactly 4 black cell phones among the chosen phones; B. there will be less than 3 black cell phones among the chosen phones.

A. 0.001   B. 0.012

Step-by-step explanation:

Since it is random selection P(B) =0.4 and P(W) =0.6

0.4^4*(0.6)^6 (A)

less than 3, can be 0,1 or 2 the probabilities of each will be determine and multiplied

its not b

step-by-step explanation:

step-by-step explanation:

x^2 -12x + 36 + y^2 = 36

x^2 + y^2 = 12x

r^2 = 12rcos(theta)

r = 12 cos(theta)