Answer:
a) The expected number of smokers in a random sample of 140 students from this university is 16.8 smokers.
b) No, it is unlikely that smoking habits and waking up early to go to the gym on Saturday are independent.
Step-by-step explanation:
To calculate the expected numbers of smokers in a sample with size n=140 and proportion p=12%, we use the expected value of the binomial distribution:

The expected number of smokers in a random sample of 140 students from this university is 16.8 smokers.
If we take a sample at the opening of the gym, the sample is not expected to be representative of the population of the students. Most of the students that go to the gym usually have healthy habits, so the proportions of smokers is expected to be lower than the average of the university population.
Answer:
I do not understand she question do you mean the sum of their income is 2640
if so, then the answer is 440 to be x income
Step-by-step explanation:
x income = 20% or 1/5 of y income
y income = 5 of x income
we know that the sum of their income = 2640
which means that
x + y = 2640 =
1/5y + y = 2640
6y/5 = 2640
cross multiply to give us
6y = 5(2640)
6y = 13200
divide through by 6 to give us,
6y/6 = 13200/6
y = 2200
since we know that x income is 20% y income,
therefore, x income =
20/100 * 2200
= 440
therefore,
x income = 440
y income = 2200
The answer for this one is exactly 8.884
Hope it helped
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