In a triangle, the total angle is 180 degrees. A straight line is always 180 degrees. With this in mind, the following can be obtained:

These are simultaneous equations.

Answer:
A
Step-by-step explanation:
-19-11 = -19 + (-11)
Answer:
Step-by-step explanation:
Leaving leap years, a year contains 365 days.
For a group of 100 people, each person is independent of the other and probability of any day being his birthday has a chance of

a) Probability that exactly 3 people have same birthday = 
Each day is independent of the other
And hence no of days having exactly 3 persons birthday out of 100 persons is binomial with n = 365 and p = 
Expected value of days = np = 
b) Distinct birthdays is binomail with p =1/365 and n = 365
Hence
expected value = np =1
Answer:
88.83
Step-by-step explanation:
To find the mean of a set of numbers is to find the average a set of numbers.
To solve for the mean you have to add all of the values together and divide that sum by the number of values there are.
Ex. 81, 97, 99, 89, 91, 76
81 + 97 + 99 + 89 + 91 + 76 = 533
533 / 6 = 88.83
↓
(number of values)