Scores on the gre (graduate record examination) are normally distributed with a mean of 600 and a standard deviation of 120. use the 68 dash 95 dash 99.7 rule to find the percentage of people taking the test who score between 240 and 960.

99.7%

Step-by-step explanation:

The 68-95-99.7 rule refers to what percentage of data is contained within ranges a certain distance from the mean.

68% of the data lies within one standard deviation of the mean

95% lies within two standard deviations, and

99.7% lies within three standard deviations.

Our mean here is 600, and our standard deviation is 120, so those ranges would be:

480-720 for 1 standard deviation

360-840 for 2 standard deviations, and

240-960 for 3.

Our given range is 240 to 960, three standard deviations from the mean, so the 68-95-99.7 rule tells us that this range contains 99.7% of the people.

38.5

step-by-step explanation:

lets say, first number = r

second number = 3r+7

total = 49

(r)+(3r+7)= 49

4r+7 = 49

4r = 42

r = 42/4

r= 10.5

3r+7 = 3(10.5)+7 = 38.5

hope this