Answer:
580 seedlings altogether.
Explanation:
Given that,
Ali plants 40% of the total number of seedlings, Ben plants 45% of the total number of seedlings, and Cliff plants the rest of the seedlings. Cliff plants 87 seedlings.
The percentage of the seedling planted by Cliff = 100% - 45% - 40% = 15%
Let x = the total number of seedlings
Hence, three boys plant 580 seedlings altogether.