Answer:




Step-by-step explanation:
The probability mass function P(X = x) is the probability that X happens x times.
When n trials happen, for each
, the probability mass function is given by:

In which p is the probability that the event happens.
is the permutation of n elements with x repetitions(when there are multiple events happening(like one passes and two not passing)). It can be calculated by the following formula:

The sum of all P(X=x) must be 1.
In this problem
We have 3 trials, so 
The probability that a wafer pass a test is 0.7, so 
Determine the probability mass function of the number of wafers from a lot that pass the test.




Answer:
if the sides are 2, 3, 4.2, 2.6 then the perimeter is 11.8
Step-by-step explanation:
just add them together
15 divided by $3.90 is $3.85. 11 divided by $3.30 is $3.33. so the answer is the rice cereal :)