Aneesha travels at a rate of 50 miles per hour. Morris is traveling 3 feet per second less than Aneesha. Which is the best estimate of the speed Morris is traveling?

1 Answer
Jun 17, 2018

A reasonable estimate of Morris's speed would be 58 miles/hour

Explanation:

The phrasing of the question implies that there should have been a list of values to choose from but no such list was provided.

3("feet")/("second")
color(white)("XXX")=3("feet")/("second") xx 60("seconds")/("minute")xx60("minutes")/("hour")

3 xx (60 xx 60) = 3 xx 3600 which is a little more that 10,000

So 3("feet")/("second") is a little more that 10,000("feet")/("hour")

There are 5,280 feet in a mile.
If we round this down to 5,000 feet per mile.

then we have an estimated speed difference of
color(white)("XXX")(10,000 "feet"/"hour")/(5,000 "feet"/"mile")=2 "miles"/"hour"

So Morris is travelling at approximately 2 "miles"/"hour" less than Aneesha's given 60 "miles"/"hour"
or at approximately 58 "miles"/"hour"

As a point of interest, using a spreadsheet to calculate the difference in traveling at 60 miles per hour versus 58 miles per hour gave a value of 2.93bar(3) feet per second; pretty close to the requested 3 feet per second.