Answer:
1/4
Step-by-step explanation:
15/60 = 1/4
Answer:
Where
and 
We are interested on this probability

And the best way to solve this problem is using the normal standard distribution and the z score given by:

If we apply this formula to our probability we got this:
And we can find this probability using the complement rule:

Step-by-step explanation:
Previous concepts
Normal distribution, is a "probability distribution that is symmetric about the mean, showing that data near the mean are more frequent in occurrence than data far from the mean".
The Z-score is "a numerical measurement used in statistics of a value's relationship to the mean (average) of a group of values, measured in terms of standard deviations from the mean".
Solution to the problem
Let X the random variable that represent the variable of interest of a population, and for this case we know the distribution for X is given by:
Where
and 
We are interested on this probability

And the best way to solve this problem is using the normal standard distribution and the z score given by:

If we apply this formula to our probability we got this:
And we can find this probability using the complement rule:

Answer:
61.64 cm
Step-by-step explanation:
The longest metal rod which could be stored in a rectangular box will be equal to its diagonal:

Answer:
i beleive it is c
Step-by-step explanation:
not completly sure
Since there are 14 boys and the whole class has 31 students
We get, the ratio of the part-to-whole relationship for boys is 14/31.
And since there are 17 girls
We get, the ratio of the part-to-whole relationship for girls is 17/31.