Are you trying to figure out the value of n?
I think it’s QT EJ and HA
Consider such events:
A - slip with number 3 is chosen;
B - the sum of numbers is 4.
You have to count 
Use formula for conditional probability:

1. The event
consists in selecting two slips, first is 3 and second should be 1, because the sum is 4. The number of favorable outcomes is exactly 1 and the number of all possible outcomes is 5·4=20 (you have 5 ways to select 1st slip and 4 ways to select 2nd slip). Then the probability of event
is

2. The event
consists in selecting two slips with the sum 4. The number of favorable outcomes is exactly 2 (1st slip 3 and 2nd slip 1 or 1st slip 1 and 2nd slip 3) and the number of all possible outcomes is 5·4=20 (you have 5 ways to select 1st slip and 4 ways to select 2nd slip). Then the probability of event
is

3. Then

Answer: 
Using SOH CAH TOA, you have the Opposite side and you need to work out the Hypotenuse so you will use SOH. This means that the opposite divided by the sine of the angle is the hypotenuse: 18/sin(35) = x = 31.4
Answer:
I think it's 20/9 hours. so 2.222222... hours.
Step-by-step explanation: