In converting measurements, we use conversion factors to multiply to the given value. For the first item, the conversion factor would be 5280 ft = 1 mi and 1 min = 60 s. We calculate as follows:
30 ft / s ( 1 mi / 5280 ft ) ( 60 s / 1 min ) = 0.34 mi / min
For the second item, we calculate as follows:
Turtle's speed: 12 mi / hr ( 5280 ft / 1 mi ) ( 1 yd / 3 ft ) (1 hr / 60 min) = 352 yd / min
Boy's speed: 4.4 ft / s ( 1 yd / 3 ft ) ( 60 s / 1 min ) = 88 yd / min