The length, width and height ratio of a cuboid is 7 : 5 : 4 and its entire surface area is 2656 square cm. Find its width.
Answer & explanation
Correct answer: option 2
l : b : h = 7x : 5x : 4x
ATQ,
T.S.A. = 2 [ lb + bh + hl ]
2656 = 2[ 35x2 + 20x2 + 28x2 ]
2656 = 2 [ 83x2 ]
83 x2 = 1328
x2 = 16
x = 4
Now,
b = 5x = 5 × 4 = 20 cm