Question

If the length of a cuboid is thrice its breadth and the breadth is twice its height, then the ratio of TSA to LSA of cuboid will be ___.

• A. 5: 2
• B. 5: 3
• C. 8: 2
• D. 5: 4

Answer 1

The correct option is A 5: 2

Let, the height of the cuboid = h
$\therefore$ breadth of cuboid (b) = 2h
length of cuboid (l) = 3(2h) = 6h

Lateral surface area
$=2(lh+bh)=2(6h\times h+2h\times h)=16h^2$
Total surface area $=2(lb+bh+lh)=2(6h\times 2h+2h\times h+6h\times h)=40h^2$
$\therefore \frac{\text{Total surface area}}{\text{Lateral surface area}}=\frac{40h^2}{16h^2}=5:2$