A square garden has a side of 20 m. How many meters of the fence is needed to enclose the garden 3 times?

Given, 

side of the square garden = 20 m

Perimeter of square garden = $4\times \mathrm{side}$

                                        = $4\times 20$

                                       = 80 m

For fencing 3 times = (3 x 80) m

                                   = 240 m