You can put this solution on YOUR website! Are you sure you have the values correct?
If you have a piece of pipe that is 29' long, you need only cut it down to make a pipe 10' long.
the answer is 1.
ETA: If the pipe is 2/9' long then you would need 90/9th to have 10 feet (90/9 = 10). Since each pipe is 2/9, you'll need 45 lengths. (90/2)