#1: The sum of q and 5
#2: Twelve times x
Please do as many as you can by yourself and ask questions about those that are hard for you.
Answer:
a) The probability that at least 5 ties are too tight is P=0.0432.
b) The probability that at most 12 ties are too tight is P=1.
Step-by-step explanation:
In this problem, we could represent the proabilities of this events with the Binomial distirbution, with parameter p=0.1 and sample size n=20.
a) We can express the probability that at least 5 ties are too tight as:

The probability that at least 5 ties are too tight is P=0.0432.
a) We can express the probability that at most 12 ties are too tight as:

The probability that at most 12 ties are too tight is P=1.
G = x
Felicia is Gabriella's age + 6
F = x + 6
Their mother is twice Felicia's age
M = 2(x + 6) or 2x + 12
Tanya is the age of their mother plus Gabriella's age
A = 2x + 12 + x = 3x + 12
3x + 12
Mr. Vella can build the wall in 4 days, however only works on it for 3 days. That means that he has completed 75% of the and is leaving 25% for his apprentice.
We need to figure out how long it takes the apprentice to build 25% of a wall. We know he can build 100% of a wall in 6 days, so dividing 6 days by 4 will give us our answer.
6/4 = 3/2 = 1.5 days
It took the apprentice 1.5 days to finish the wall.
7 + 3.(2 - 3x) = 67
3 brackets are distributed
7+6-9x = 67
13-9x = 67
-9x = 67
x = 67/-9