Answer:
133 pieces of 15cm can be cut from the ribbon.
Step-by-Step Explanation:
Length of ribbon = 20 meters
Length needed to be cut = 15 cm
We will convert meters into centimeters.
1 meter = 100 cm
20 meters = 2000 cm
Number of pieces = 
Number of pieces = 133.33
Rounding off to nearest whole number = 133
Hence,
133 pieces of 15cm can be cut from the ribbon.
Answer:
0.0266, 0.9997,0.7856
Step-by-step explanation:
Given that the IQs of university​ A's students can be described by a normal model with mean 140 and standard deviation 8 points. Also suppose that IQs of students from university B can be described by a normal model with mean 120 and standard deviation 11. Let x be the score by A students and Y the score of B.
A)
B) Since X and Y are independent we have
X-Y is Normal with mean = 140-120 =20 and 

C) For a group of 3, average has std deviation = 

Answer:

Step-by-step explanation:
From the given information;
the probability of getting returned p = 0.1
If eight rings are sold today, what is the probability that fewer than three will be returned;
According to binomial distribution
Binomial distribution is the probability of success or failure of an outcome of an experiment under observation which is usually repeated several trials. Binomial experiments are random experiment with fixed number of repeated experiment. If we cannot predict before head, the outcome of an experiment , the experiment is called a random experiment.
So , using binomial distribution to determine the probability that fewer than three will be returned;
i.e

