The dimension of the base of an open rectangular box is 5cm \times 3cm. If the volume of the box is 30 cm^3, then the total surface area of the box is…
Let the height of the box is t. Hence 5\times 3\times t=30. It follows that t=2 cm.
Now the surface area of the box is made up of two rectangles of size 3 by 5$, two rectangles of size 3 by 2 and two rectangles of size 5 by 2.
Therefore the surface area is 2(3\times 5)+2(3\times 2)+2(2\times5)=30+12+20=62 centimeter squared.