Stella and Twinkle are filling up a truck with a capacity of 6000 stone blocks at the rate of 250 blocks per hour per person. They work for four hours and are then joined by 6 other people who also work at the same rate. How many hours did filling the truck take?
How many blocks did Stella and Twinkle fill up the truck in an hour? ** Stella and Twinkle filled up the truck at the rate of 250 blocks per hour per person, a total of 2*250 = <<250*2=500>>500 blocks per hour for both.
How many blocks did Stella and Twinkle fill up the truck in four hours? ** After working for four hours, Stella and Twinkle had filled 4*500 = <<4*500=2000>>2000 blocks into the truck.
How many blocks did Stella and Twinkle have to put into the truck for it to be full? ** The number of blocks they had to put into the truck for it to be full is 6000-2000 = <<6000-2000=4000>>4000
How many people were filling the truck now? ** When 6 more people joined Stella and Twinkle, a total of 2+6 = <<2+6=8>>8 people were filling the truck now.
How many blocks did the eight people fill the truck in an hour? ** Working at the rate of 250 blocks per person, the eight people filled the truck with 250*8 = <<250*8=2000>>2000 blocks in one hour.
How many hours did the 8 people take to fill the truck? ** If there were 4000 blocks that still needed to be put into the truck, the 8 people took 4000/2000 = <<4000/2000=2>>2 hours to fill the truck with the blocks.
How many hours did filling the truck take? ** The total time it took to fill up the tank is 4+2 = <<4+2=6>>6 hours.
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