the heights of a wall is 6 times its width and the length of the wall is 7 times its height . if volume of the wall be 16128 cu . m , its width is  Choose the correct answer:
A) 4 m	B) 4.5 m	C) 5 m	D) 6 m	E) none

Rationale: solution let the width of the wall be x metres . then , height = ( 6 x ) m and length = ( 42 x ) m . 42 x × x × 6 x = 16128 x 3 ‹ = › ( 16128 / 42 × 6 ) = 64 ‹ = › x = 4 . answer a
Answer: A