Bunuel
Official Solution:
If a cube with a side length of 4 cm is cut into smaller cubes, each with a side length of 1 cm, what is the percentage increase in the total surface area of the resulting smaller cubes?
A. 4%
B. 166%
C. 266%
D. 300%
E. 400%
A cube has 6 faces.
The surface area of a cube with a side length of 4 cm is \(6*4^2 = 6*16\) square centimeters.
Given that the volume of the larger cube is \(4^3 = 64\) cubic centimeters and the volume of each smaller cube is \(1^3 = 1\) cubic centimeter, the larger cube can be divided into \(\frac{64}{1} = 64\) smaller cubes. Each of these smaller cubes has a surface area of \(6*1^2 = 6\) square centimeters, resulting in a total surface area of \(6* 64\) square centimeters for all 64 smaller cubes.
The total surface area of the smaller cubes, \(6*64\), is 4 times greater than the surface area of the larger cube, \(6*16\), which corresponds to a 300% increase.
Alternatively: To calculate the percentage increase, use the formula for percent change: \(\text{Percent} = \frac{\text{Change{\text{Original *100\).
The percentage increase can be calculated as follows: \(Percent = \frac{\text{Change{\text{Original *100 = \frac{6*64 - 6*6}{6*16}*100 = 300\%\).
Answer: D
Hi bunnel, shoudn't the larger cube be divided into 256 smaller cubes with side of 1cm each - since right now we have one cube with side 4cm each. If we have 64 smaller cubes, won't there be a part of larger cube left?