Question

a wildlife photographer photographs a crocodile and then paddles against a river current for 6 km. Then, hoping to photograph a hippopotamus, she paddles 15 km across a lake. She paddles across the lake for one hour longer than she paddled up the river. find the speed of the boat as she paddles the lake if the river current is 2 km/h. Pls answer. You'll get 100 points.

Answer 1

5 km/h or 6 km/h

Explanation:

Let the speed of the boat be x

Speed against the current in the river is x - 2

Time in the river:

6/(x - 2)

Time in the lake:

15/x

The difference:

6/(x - 2) = 15/x - 1

Solve for x to find the speed of the boat

Multiply both sides by x(x - 2) to clear the fraction:

6x = 15(x - 2) - x(x - 2)

6x = 15x - 30 - x² + 2x

x² - 11x + 30 = 0

(x - 5)(x - 6) =0

x -5 = 0, x - 6 = 0

x = 5 km/h, x = 6 km/h

Answer 2

• 5 km/h or 6 km/h

Explanation:

• Let the speed of the boat be x
• Speed against the current in the river is x - 2

Time in the river:

• 6/(x - 2)

Time in the lake:

• 15/x

The difference:

• 6/(x - 2) = 15/x - 1

Solve for x to find the speed of the boat

Multiply both sides by x(x - 2) to clear the fraction:

• 6x = 15(x - 2) - x(x - 2)
• 6x = 15x - 30 - x² + 2x
• x² - 11x + 30 = 0
• (x - 5)(x - 6) =0
• x -5 = 0, x - 6 = 0
• x = 5 km/h, x = 6 km/h