Question

What will be the length of the longest wafer roll that can fit completely inside the given chocolate box?

• A. 12 units
• B. 14 units
• C. 28 units
• D. 24 units

Answer 1

The correct option is B 14 units

In the given figure:


Both △ABC and △ACD are right angled traingles.

Applying pythagoras theorem in △ABC:
$A{B}^2+B{C}^2=A{C}^2$
$\Rightarrow {12}^2+6^2=A{C}^2$
$\Rightarrow 144+36=A{C}^2$
$\Rightarrow A{C}^2=180\text{sq. units}$

Similarly, applying pythagoras theorem in △ACD:
$A{D}^2=A{C}^2+D{C}^2$
$\Rightarrow A{D}^2=180+4^2$
$\Rightarrow A{D}^2=196$

$\therefore AD=14\text{unit}$

So, the length of longest wafer roll that can completely fit inside the chocolate box is 14 units.