Mariah can swim 100 meters in 1 minute and 40 seconds. As long as her swimming speed remains constant, how fast can she swim 250-meter race?

Answer 1

Since 250 is 2.5 x 100, it would take 2.5 x (1 hour, 40 minutes) time to go 250 meters

40 minutes = .667 hours, so, using a ratio 1.667 hours/100 meters = x hours/250 meters

or

x = 1.667(250)/100 = 2.5(1.667) = 4.17 hours.