Answer:
30 minutes
Step-by-step explanation:
Nathaniel can weld 1 rail in 75 minutes, so he welds 1R = 75 min, and Brenda can weld 1 rail in 50 minutes (25 minutes faster than Nathaniel), so she welds
1R = 50 min
We want to see how many minutes it takes them both, so we need to solve both problems for the minute unit
Nathaniel: (1/75)R = 1 min (he can do one seventy-fifth of a rail per minute)
Brenda: (1/50)R = 1 min (she can do one fiftieth of a rail per minute)
notice, the equation is 1/(minutes it takes them), and we want to see how long it takes both of them, so we get the equation:
1/75 + 1/50 = 1/x
Simplify the left side with common denominator of 57(50) = 3750
We get
125/3750 = 1/x
We can cross multiply to get rid of the fractions...
125x = 3750
Divide both sides by 125 to solve for x...
x = 30, so it would take them 30 minutes to weld a rail if they work together.
Answer:
C. populations are non normal and the sample sizes are large.
Step-by-step explanation:
To test hypotheses about the difference between two populations means we deal with the following three cases.
1) both the populations are normal with known standard deviations.
2)both the populations are normal with unknown standard deviations.
3) both the populations are non normal in which case both the sample sizes are necessarily large.
So option C is the correct answer.
Answer:
look it up on symbolab
Step-by-step explanation:
290 mph , its going half the speed as before. Hope this helps.
Answer:
13,000,000+200,000+60,000
Step-by-step explanation:
