6:18 students in Debra's class own a cellphone. Because there are 24 people in total. Minus the people who already own cellphones. Leaving 18 without cellphones. The ratio is people who have cellphones to people who do not.
24-6=18. Thus, the ratio would be 6:18
-4, because it is four units away from zero.
We know that
3600 seconds = 1 hour
Then
3400 seconds = 3400/3600
= 17/18 hours
5280 feet = 1 mile
Then
63360 feet = 63360/5280 mile
= 12 mile
So
Distance covered by Nina in 17/18 hours = 12 mile
Then
Distance covered by Nina in 1 hour = 12/(17/18) miles
= 12.71 miles.
From the above deduction, we can conclude that the speed of Nina is 12.71 miles per hour.
Speed of Sophia is 10 miles per hour. So Nina is the girl that rides at a faster speed.