Question
A boat can travel at 16 km/h in still water. If the speed
of the current were 6 km/h faster than it actually is, it would take the boat 15 hours longer to cover 180 km upstream than it does with the current actual speed. What is the speed of the current?Solution
Let the speed of the current be ‘x’ km/hr
According to the question,
{180/(16 – x – 6)} – {180/(16 – x)} = 15
Or, x 2 – 26x – 88 = 0
Or, x 2 – 22x – 4x + 88 = 0
x = 22, 4
Since, the speed of the current cannot be more than the boat, therefore speed of the current = 4 km/hr
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