Question

How many planks each of which is 3 m long, 15 cm broad and 5 cm thick can be prepared from a wooden block 6 m long, 75 cm broad and 45 cm thick?

Answer 1

Length of the wooden block = 6 m

\[ = 6 \times 100 cm ( \because 1 m = 100 cm)\]

 = 600 cm

Breadth of the block = 75 cm

Height of the block = 45 cm

\[\text { Volume of block = length } \times \text { breadth } \times \text { height }\]

\[ = 600 \times 75 \times 45\]

\[ = 2025000 {cm}^3 \]

Again, it is given that the length of a plank = 3 m

\[ = 3 \times 100 cm ( \because 1 m = 100 cm)\]

 = 300 cm

Breadth = 15 cm, 

Height = 5 cm

\[\text { Volume of the plank = length } \times\text { breadth } \times \text { height }\]

\[ = 300 \times 15 \times 5 = 22500 {cm}^3 \]

\[ \therefore\text {  The number of such planks } = \frac{\text { volume of the wooden block }}{\text { voume of a plank }} = \frac{2025000 {cm}^3}{22500 {cm}^3} = 90\]