Answer:

Step-by-step explanation:
As the numbers are only between 1 and 30
Total number of possible combinations = 30×30×30 = 27000
If there are 100 attempts then

∴ Probability someone can guess the correct combination given 100 attempts is 
Answer:
i think that the answer would be but im not 100% sure
Step-by-step explanation:
F(x) = 1 - x
f(-3) = 1 - (-3)
f(-3) = 4
Answer:
The probability of Javier volunteers for less than three a month is 25%
Step-by-step explanation:
According to the questions,
The probability of Javier to attend exactly 5 events :-
P ( x = 5 ) = 25% = 
The probability of Javier to attend exactly 4 events :-
P ( x = 4 ) = 
The probability of Javier to attend exactly 3 events :-
P ( x = 3 ) = 
The probability of Javier to attend exactly 2 events :-
P ( x = 2 ) = 
The probability of Javier to attend exactly 1 events :-
P ( x = 1 ) = 
The probability of Javier to attend no events :-
P ( x = 0 ) = 
Now we have to calculate the probability of Javier volunteers for less than three P ( x < 3 ).
P ( x < 3 ) = P ( x = 0 ) + P ( x = 1 ) + P ( x = 2 )
P ( x < 3 ) =
=
=
= 0.25 = 25 %.