Answer:

Step-by-step explanation:
From the given information:
The diagrammatic interpretation of what the question is all about can be seen in the diagram attached below.
Now, let V(x) be the time needed for the runner to reach the buoy;
∴ We can say that,

In order to estimate the point along the shore, x meters from B, the runner should stop running and start swimming if he want to reach the buoy in the least time possible, then we need to differentiate the function of V(x) and relate it to zero.
i.e
The differential of V(x) = V'(x) =0
=





squaring both sides; we get


By cross multiplying; we get










Answer:
b
Step-by-step explanation:
Surface of the earth =3959×3.14
=12,437.565
if 20%is suitable so we multiply it by the surface
12,437.565×0.2=2,487.513 per people
2,487.513/7,700,00,00
So I think it will be the closest to b
Answer: 140
Step-by-step explanation: since 4 = 40 then 2 would also be 40 because they are the same angle (Keep in mind that a line is 180 degrees) 180-40=140! Good luck! :D
The product of any number and its reciprocal is ' 1 '.
Call the number ' Q '.
Whatever the number is, its reciprocal is 1/Q .
Their product is
( Q ) x ( 1/Q ) = ( Q/Q ) = 1