Short Answer: Current speed = 3 miles per hour.
Givens
Downstream
d = 4.48 miles
t = 0.32 hours.
c = ??
r_boat = ??
Upstream
d = 4.48 miles
t = 0.56 miles
c = ??
r_boat =??
Equations.
Since the distances are the same, you can equate the distances and come back to them later.
d = r*t
(r - c) * 0.56 = (r + c) * 0.32 This will give you r in terms of c. Notice the minus sign on the left. It's there because the current is going against you, slowing you down.
Remove brackets
0.56r - 0.56c = 0.32r + 0.32c Add 0.56c to both sides.
0.56r = 0.32r + 0.32c + 0.56c
0.56r = 0.32r + 0.88c Subtract 0.32r from both sides.
0.56r - 0.32r = 0.88c
0.24r = 88c Divide by 0.24
r = 0.88/0.24 c
r = 3 2/3 c
Now we have enough information to solve for c
4.48/(r + c) = 0.32
4.48 = 0.32 * (r + c) Substitute r = 3 2/3c into this equation.
4.48 = 0.32 * (3 2/3c + c) Add c and 3 2/3c together.
4.48 = 0.32 * (4 2/3c) Change 4 2/3 to 14/3
4.48 = 0.32 * 14/3 c
4.48 = (4.48 / 3 ) * c
4.48 = 1.493333333 c Divide 4.48 by 1.493333333
c = 4.48 / 1.4933333
c = 3 mph <<<<<<<<<<<<<<Answer
Decimal pt after 3 digits in first number so 3 digits in product.
Area of the two side triangles: 10 and 10 = 20
A = 1/2 bh
A = (10*2)/2 = 10
Area of rectangle:
A = l x w
A = 10 * 9
A = 90
90 + 20 = 110
The answer to your question is -20 i hope this helps!
The answer & explanation for this question is given in the attachment below.