Question

A cyclist averages 18.5 miles per hour. how many minutes will it take for him to complete a 125 kilometer race?

Answer 1

step 1
convert miles to km
1 mile is-----> 1.60934 km
18.5 miles/hour-----> 18.5*1.60934=29.77 km/hour

step 2
convert km/hour to km/minutes
29.77 km/hour--------> 29.77/60----> 0.4962 km/minutes

step 3
by proportion
0.4962 km/1 minutes=125 km/x minutes
0.4962 km----------> 1 minute
125 km-------------> x

x=125/0.4962----> x=251.91 minutes---------> x=251.9 minutes

the answer is
251.9 minutes

Alternative Method

step 1
convert km to miles
1 km is-----> 0.621371 miles
125 km-----> 125*0.621371--->77.67 miles

step 2
convert miles/hour to miles/minutes
18.5 km/hour--------> 18.5/60----> 0.3083 miles/minutes

step 3
by proportion
0.3083 miles/1 minutes=77.67 miles/x minutes
0.3083 miles----------> 1 minute
77.67 miles-------------> x

x=77.67/0.3083----> x=251.9 minutes