Answer :
It would take 5 hours.
1/15 of the lawn in 1/3 hours means it takes 1 hour to water 3/15 of the lawn aka 1/5
1/5 of the lawn in 1 hour would mean it takes 5 hours to finish watering the entire lawn.
It would take 5 hours.
1/15 of the lawn in 1/3 hours means it takes 1 hour to water 3/15 of the lawn aka 1/5
1/5 of the lawn in 1 hour would mean it takes 5 hours to finish watering the entire lawn.