The question asks for the unit rate when 1/4 of a kilometer is covered in 1/3 of an hour.
Recall that rate is the quotient of two quantities. In our case the numerator is the distance (1/4) of a kilometer, and the denominator is the time: 1/3 of an hour.
So, we perform the following division of fractions:
1/4 diided by 1/3 which is the same as: 1/4 times 3/1 = 3/4
and since we are asked for the UNIT rate, we do the actual division:
The unit rate is 0.75 km per hour.
