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.