Answer:
The speed of the first train is 45 mph and the speed of the second train is 75 mph
Step-by-step explanation:
Let x represent the speed of the first train in mph. Since the second train, is 30 mph faster then the first, therefore the speed of the second train is (x + 30).
The first train leaves at 1:00 pm, therefore at 6:00 pm, the time taken is 5 hours. Therefore the distance covered by the first train at 6:00 pm = x mph * 5 hours = 5x miles
The second train leaves at 3:00 pm, therefore at 6:00 pm, the time taken is 3 hours. Therefore the distance covered by the second train at 6:00 pm = (x + 30) mph * 3 hours = (3x + 90) miles
Since the second train overtakes the first at 6:00 pm, hence:
3x + 90 = 5x
2x = 90
x = 45
Therefore the speed of the first train is 45 mph and the speed of the second train is 75 mph (45 mph + 30 mph).
19,000
Step-by-step explanation:
round down if the hundred is above 5 than round up one number
It is 6 :D
explanation: t
Answer:
So the answer for this case would be n=247 rounded up to the nearest integer
Step-by-step explanation:
We know that the standard deviation is :
represent the deviation
The margin of error is given by this formula:
(a)
And on this case we have that ME =25 and we are interested in order to find the value of n, if we solve n from equation (a) we got:
(b)
The critical value for 95% of confidence interval now can be founded using the normal distribution and the critical value would be 
, replacing into formula (b) we got:
So the answer for this case would be n=247 rounded up to the nearest integer
