Atrain travels at a speed of 30 miles per hour. if 1 mile = 1.6 kilometers, how fast is the train traveling in kilometers per minute?
a- 1.0 km/min
b- 0.4 km/min
c- 0.8 km/min
d- 0.6 km/min

The answer 
 the speed of the train traveling in kilometers per minute can be found by using the following method:
v = 30 miles per hour
1 mile = 1.6 kilometers

just do the calculus by changing miles to kilometers
 1 mile = 1.6 kilometers, so 30 miles= 1.6 km x 30 = 48 km
 so the speed of the train is
v=30 miles / hour = 48km / h = 48km / 60 mn  = 0.8 km/ mn
the answer is
C- 0.8 km/min