if the wheel of an engine of a train 4 2/7 in circumference makes seven revolutions in 4 seconds, the speed of the train is

Question

if the wheel of an engine of a train 4  2/7 in circumference makes seven revolutions in 4 seconds, the speed of the train is

anonymous · Answer

1 minute, it makes 30 meter's

anonymous · Answer

in 4 sec the wheel makes 7 turns of 30/7 inches
so in 4 sec it covers 7x30/7 inches = 30 inches
4 sec x15 = 30in x 15
60 s = 450 in
so in 1 min it covers 450 inch
in one hour it covers 450 x 60 inch
i.e. in one hour it covers 27000 inch
but 1 inch = 2.54 cm
so in 1 hour it covers 27000 x 2.54 cm = 68580 cm

since the train is covering 68580 cm in 1 hour
means it is covering 685.8 m in 1 hour

so speed of train is 685.8m/h