![In a direct rope haulage operating along a 1500 m long incline](https://www.gkseries.com/blog/wp-content/uploads/2023/10/In-a-direct-rope-haulage-operating-along-a-1500-m-long-incline.jpg)
Q. In a direct rope haulage operating along a 1500 m long incline, 180 tonne of coal is hauled in 7 hours. The average rope speed is 7.5 km/h. The set changing time for the tubs is 2 minutes each at the top and bottom of the incline. If the tub capacity is 1.0 tonne, the number of tubs in the set is .