The speed to the island is x. The speed to return is x+5.
The distance is the same so, 2.5 multiplied by x = 2×(x+5).
It took 2.5 hrs to get there and 2 hrs to return. Now all we have to do is solve.
2.5*x = 2x + 10
.5x = 10
x=20
Therefore, the distance between islands is 2.5 × 20 = 50 miles.
hope this helps!
Answer:
A sample of 997 is needed.
Step-by-step explanation:
In a sample with a number n of people surveyed with a probability of a success of
, and a confidence level of
, we have the following confidence interval of proportions.
In which
z is the z-score that has a p-value of
.
The margin of error is of:

A previous study indicates that the proportion of left-handed golfers is 8%.
This means that 
98% confidence level
So
, z is the value of Z that has a p-value of
, so
.
How large a sample is needed in order to be 98% confident that the sample proportion will not differ from the true proportion by more than 2%?
This is n for which M = 0.02. So






Rounding up:
A sample of 997 is needed.
The correct answer is C
Hope this helped!
120 degrees or 0.67 radians
I'm pretty sure it would be 14:854