From a wooden log with a length of 5 dcm, and a breadth of 5 dcm. and the thickness of 3 dcm, 40 planks are of 2 dcm length and 2 dcm breadth are cloven. For cleaving wood has been destroyed. But still, now 108 cubic dcm of wood remains in the log. What is the thickness of each plank that is cloven, let us calculate and write it.

The total volume of the log =40 dcm × 5 dcm × 3 dcm.

= (40 × 5 × 3) cu dcm.

= 600 dcm

Total volume of wood wasted = 600 × \frac{2}{10} = 12cu dcm.

Let the thickness of each plate = x dcm.

\therefore Volume of each plate = 20 × 2 × x cu dcm.

Volume of 40 plate = 40 ×(20 × 2 × x) = 1600 × cu.dcm.

According to the problem,

1600 x + 108 + 12 = 600

1600 x = 600 – 120 = 480

∴ x = \frac{480}{1600}= 0.3 dcm .

∴ The thickness of each plate = 0.3 dcm.