How much space, in cubic units, is left vacant when maximum number of 2x2x2 cubes are fitted in a rectangular box measuring 8x10x9 ?  Answers
A) 60	B) 65	C) 70	D) 75	E) 80
No of cubes that can be accommodated in box = (8*10*9)/(2*2*2)   8*10 in numerator can be perfectly divided by 2*2 in denominator.   side with length 9 can't be perfectly divided by 2 and hence is the limiting factor. Closet multiple of 2 less that 9 is 8. so vacant area in cube =   =10*8 (9-8)   =10*8*1= 
<gadget id="calculator">10*8*1</gadget>
<output>80</output>
80   Ans - 80
<result>E</result>
How much space, in cubic units, is left vacant when maximum number of 2x2x2 cubes are fitted in a rectangular box measuring 8x10x9 ?