# Tree-Planting Problem

• Jun 21st 2009, 11:50 PM
gaurav517
Tree-Planting Problem
There are 18 plants to be planted in 9 rows with 5 plants in each row. Can anyone please give a diagram?
• Jun 22nd 2009, 04:03 AM
aidan
Quote:

Originally Posted by gaurav517
There are 18 plants to be planted in 9 rows with 5 plants in each row. Can anyone please give a diagram?

It should be obvious that some plants MUST appear in more than 1 row simultaneously.

If you placed one plant in the center with 9 radiating lines and a plant at the end of each line, you would have a total of ten plants with 9 lines. 8 plants remaining. Since the 8 cannot be divided by the 9 lines, it means that some plants must also appear in three different lines at the same time.
• Jun 22nd 2009, 05:54 PM
wytiaz
Quote:

Originally Posted by gaurav517
There are 18 plants to be planted in 9 rows with 5 plants in each row. Can anyone please give a diagram?

No one said the plants must be of uniform size.

Make 9 rows, put 2 plants per row, then fatten up plants to invade other rows.