area of rectangular plot = length * breadth

= 120 * 40 =480M.sq.

therefore, 480/6 = 80

ans. 80 trees can be planted

Distance between  n Trees  = (n - 1) * (Distance between two trees)

=> n = Distance between  n Trees / (Distance between two trees)   + 1

Length = 120 m

Number of trees  =  (120/6) + 1  = 21

Breadth  =  90 m

Number of trees = (90/6) + 1 = 16

Corner tress are counted twice

=> number of trees = 2(21 + 16) - 4

=> number of trees = 2(37) - 4

=> number of trees = 74 - 4

=> number of trees =   70  

number of trees =   70

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