It takes a boy 30 minutes to mow the lawn, but his sister can mow it in 45 minutes. how long would it take them to mow the lawn if they worked together, using two lawn mowers?

Hence they together will mow the lawn in 18 minutes

answer is 144

step-by-step explanation:

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.