saplings of ashokatree have to be planted 3 metres from each other and neem trees are to be planted at 7 metres from each other. find out the smallest size of land in which they can be planted in rows of smilar kind

Answer :

Given  : Saplings of ashoka tree have to be planted 3 metres from each other and neem trees are to be planted at 7 metres from each other .

To find out smallest length of land we find LCM of 3 and 7 .

And

LCM ( 3 and  7 ) = 3 $\times$ 7 = 21

So,
Smallest length of land  = 21 m                                              ( Ans )