Stanley drove his car on a business trip. when he left, the mileage was 840 miles, and when he returned, the mileage was 1,200 miles. the car used 12 gallons of gasoline for this trip

54 kilometers per hour

step-by-step explanation:

according to rules:

1 km = 1000 meter

which means that 1 meter = 1/1000 km

1 hour = 3600 second [ as 1 hour = 60 min = 60 *60 seconds ]

which means that 1 second = 1/3600 hour

therefore, 1 kilometer/hour =

thus to convert 15 meter per second to kilometer per hour, we multiply 15 to 3.6 kilometer/hour.

15 meter/second=   which is the required answer.

75%

step-by-step explanation: