Let the youngest sister be n years
Lana will be 2n years, as her youngest sister is half her age
The age of the twins separately will be 2n-2 as they are 2 years younger than Lana
So, the equation looks like this:
n + 2n + 2(2n-2) = 45
Now solve for n:
3n + 4n - 4 = 45
7n - 4 = 45
7n = 49
n = 7
So the youngest sister is 7, Lana is 14 and the twins are 12. 14 + 12 + 12 + 7 =45
Answer:
a.


b.


c.
Attached file
d.
Apparently the practice of smoking reduces the ability to fall asleep, demanding much more time in individuals who smoke, than in those who do not smoke.
Step-by-step explanation:
a, b) For the group of smoking individuals, the average time it takes to fall asleep and the standard deviation of those times is:


a, b) For the group of non-smoking individuals, the average time it takes to fall asleep and the standard deviation of those times is:


c. In the attached file you can see the diagram of points for the times, in the smoking and non-smoking groups.
d. Apparently the practice of smoking reduces the ability to fall asleep, demanding much more time in individuals who smoke, than in those who do not smoke.
Answer:
<em>X ball bearings will be made in 1 hour and 20 minutes</em>
Step-by-step explanation:
<u>Proportions
</u>
The proportions give us an important tool to easily solve common problems of any type. We know that:
Company ABC can make X ball bearings in 3 hours.
Company DEF can make X ball bearings in 4 hours.
Company GHI can make X ball bearings in 6 hours.
In one hour, each company can make
ABC: X/3 ball bearings
DEF: X/4 ball bearings
GHI: X/6 ball bearings
Working together, they can make
ball bearings. Operating
If they can make 3/4 of a ball bearing in one hour, then one complete ball bearing will need
hours to complete. It's equivalent to 1 1/3 hours or 1 hour and 20 minutes
X ball bearings will be made in 1 hour and 20 minutes
Possible values = 3.0 and 6.0
6 - 3 = 3
The difference is 3