Question

The total surface area of all six sides of the rectangular box is equal to $80$ square inches. What is the volume of the rectangular box in inches cubed?

• A. $40$
• B. $48$
• C. $12$
• D. $30$

Answer 1

The correct option is B $48$

We will first find the total area of all the six sides of the box by taking the third side as $x$
The area of the left and the right sides
$=4x+4x=8x$
The area of the front and back sides
$=4x+4x=8x$
The area of the top and bottom sides $=16$+$16=32$ sq. inches
Now to find the value of $x$, we get the equation as
$80=$ $8x+8x+32$
$=$ $16x+32$
$\therefore 16x=80-32$
$\therefore 16x=48$
$\therefore x=\frac{48}{16}$
$\therefore x=3$
Volume of the rectangular box $=$ $4\times 4\times 3$ inches cubed.
The correct answer is option B i.e. $48$.