Understanding Unit Rates

Question

Thuy drives 270 miles in 6 hours. How many miles does Thuy drive in 13 hours?

Answer 1

A unit rate is a measure of the amount of one variable for just one of another variable.

 

Here, the units are "miles" and "hours."  One unit rate is:  miles per hour, or miles/hour.

    [note: another unit rate is hours/mile]

 

Unit rate:

    (270 miles)/(6 hours)

     (45 miles)/(1 hour)

       45 miles per hour

 

The (distance) = (miles per hour)*(hours)                  [note: hours cancel out]

    distance = (45 mi/hr)*(13 hr)

    distance =  585 miles

 

Note: to determine the time required to travel 585 miles at a rate of (1 hour)/(45 miles), we would calculate:

           ( (1 hour)/(45 miles) ) * (585 miles)          [note: miles cancel out]

               13 hours

Answer 2

270/6=m/13

cross multiply

6*m=13*270

6m=3510

m=3510/6

m=585 miles

or,...

270/6=45 miles/1 hour

13 hours*45 miles=585 miles