[SPM Maths] Hii can anyone help me with this question? The answer is C


Rajah 1 menunjukkan sebongkah logam berbentuk prisma.
Diagram 1 shows a prism-shaped piece of metal.

Logam itu dileburkan untuk membentuk beberapa kubus kecil yang berjisim 5g setiap satu. Diberi bahawa ketumpatan logam itu ialah 3100kg/m^3 cari bilangan kubus yang dibentuk. [ketumpatan = \frac{Jisim}{isipadu}].
The metal is melted to form several small cubes weighing 5g each. Given that the density of the metal is 3100kg/m^3, find the number of cubes that can be formed. [Density=\frac{Mass}{Volume}]
A 3.72 \times 10^4
B 3.72 \times 10^{-4}
C 7.44 \times 10^6
D 7.44 \times 10^{-6}


Hi Ben,
If you look closely, you can tell that the prism actually comes from a cuboid that is cut diagonally, so we just use ½ × volume of cuboid to find its volume.

After that, we have to find the volume of one small cube. Since the question already gave the density and mass, we simply use the density= mass / volume formula to solve.

Finally, we divide the bigger volume by the smaller volume to see how many small cubes make up to 12m³. Both of the volumes are in m³, so the units cancel off as it should be. The final answer we get is a number with no units.

Hope this helps! :slight_smile:

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