A boat travels 4 miles downstream in half an hour, and the same distance upstream in 2 hours. What is the speed of the boat in still water?

7/3 mph

Step-by-step explanation:

knowing that:

distance traveled = velocity * time - velocity of the water * time

4 = v1 * 1.5 + v2 * 1.5

4 = v1 * 2 - v2 * 2

solve the system in any way you want,

v1 = 7/3 miles per hour

v2 = 1/3 miles per hour

u = -(6/7)w

step-by-step explanation:

place all values with 'u' on one side of the equation.

4u + 8w = - 3u + 2w

4u + 3u = 2w - 8w

further simplify the equation by solving the addition and subtraction.

7u = - 6w

make 'u' the independent variable by placing its co-efficient on the right-hand side.

u = - (6/7)w

step-by-step explanation:

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