It will take 49 minutes for 9 people to paint 7 walls
Answer:
-25
Step-by-step explanation:
First he bought 3 tires which total costed 105, then returned 2, so he got $70 back, meaning he had $35. Then he found 2 $20 bills, which raised his total to $75. Then, he bought a phone for $90, so he has -25 dollars left
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.




The answer to the question is c
The answer is 313.56 because 289 + (8.5%=24.65)=313.56