In 2 hours, the train will cover 120 miles, in 4 hours, the train will cover 240 miles. The train covered 120 more miles in 4 hours than it did in 2 hours.
For this question you would simply divide the number of bamboo poles by the number of feet which would be:
6,500/624= 10.41666666666667
Since it says to round to the nearest whole number,
Your answer would be about 10 bamboo poles per feet
