Answer:
w=7 and l=10
Step-by-step explanation:
To find the dimensions, create an equation for its perimeter and solve. Recall, the perimeter formula for a rectangle is P = 2l+2w. P is 34 cm. L is 4cm less than twice the width or 2w-4. And the width is w.
P = 2l+2w
34 = 2(2w-4) + 2w
34 = 4w -8 +2w
34 = 6w -8
34+8 = 6w
42 = 6w
7=w
The width is 7 cm. To find the length substitute w=7 into l=2w-4.
l=2w-4
l=2(7)-4
l=14-4
l=10
Answer:
- 3 hours
- 1 hour 45 minutes
- 300 miles
Step-by-step explanation:
1. The trains are moving toward each other at a total speed of 50 +20 = 70 miles per hour. Together, they cover the 210 mile distance in ...
time = distance/speed
time = 210 mi/(70 mi/h) = 3 h
The trains collide after 3 hours.
__
2. The fly is closing with the freight train at a speed of 100 +20 = 120 miles per hour. Together, the fly and the train cover the initial 210 mile distance in ...
(210 mi)/(120 mi/h) = 7/4 h = 1 hour 45 minutes
The fly first meets the oncoming freight train after 1 h 45 min.
__
3. The fly is flying for all three hours before the trains collide, so, at 100 miles per hour, will fly 300 miles.
Answer:
b.
Step-by-step explanation:
angles A & L are not equal
sides are not proportional <u> 4 </u> ≠ <u> 5.6 </u>
6 8
Answer:101
Step-by-step explanation:
U just add all the numbers together
Answer:
n=1705
Step-by-step explanation:
The margin of error is the range of values below and above the sample statistic in a confidence interval.
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".
Assuming the X follows a normal distribution
And the distribution for 
is:
We know that the margin of error for a confidence interval is given by:
(1)
The next step would be find the value of 
, 
and 
Using the normal standard table, excel or a calculator we see that:
If we solve for n from formula (1) we got:
And we have everything to replace into the formula:
And if we round up the answer we see that the value of n to ensure the margin of error required 
mm is n=1705.
