Speed and Distance

In Algebra 2, we may be asked to look at rates. Often these come in the form of speed and distance questions. The general formula for this type of problem is Distance = rate * time. Here is an example problem:

A man can row at 6 km/hin still water. The speed of the river he now rows in is 4 km/h. How long will it take him to row upstream 30 km?

Using the formula distance= rate*timewe will rearrange it to solve for time. Now, distance/rate= time. Our distance is a 30 km and our rate is his speed in stillwater minus the current speed. So, (30km)/(6-4 km/hr)= time. Simplifying, (30km)/(2km/hr)= time. Finally, time equals 15 hours.

Oar propelled ship. Abraham Willaerts (circa 1603–1669).

Oar propelled ship. Abraham Willaerts (circa 1603–1669).

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