Answer:
8
Step-by-step explanation:
The surface area of a sphere is 4r^2pi, so dividing 100 by 4pi gives a result of 25/pi. Taking the square root and rationalizing the denominator, we have 5sqrt(pi)/pi as the radius of the sphere.
Let the speed of the current equal c
and the speed of the boat in still water equal b.
b + c = 1.5 (b - c)
b + c = 1.5b - 1.5c
0.5b = 2.5c
b = 5c
The speed of the current is 1.5 mph so
b = 5 * 1.5 = 7.5 mph
The answer is
u = -15, hope this helps!
