soniadiana2011 wrote:A carpenter constructed a rectangular sandbox with a capacity of 10 cubic feet. If the carpenter were to make a similar sandbox twice as long, twice as wide, and twice as high as the first sandbox, what would be the capacity, in cubic feet, of the second sandbox?

Say, the first sandbox is a feet long, b feet wide, and c feet high.
Hence, volume of the first sandbox = abc = 10 cubic feet

Now, the second sandbox is 2a feet long, 2b feet wide, and 2c feet high.
Hence, volume of the second sandbox = (2a)*(2b)*(2c) = 8abc = 8*10 cubic feet = 80 cubic feet

The correct answer is D.

Hi All,

We're told that a carpenter constructed a rectangular sandbox with a capacity of 10 cubic feet. We're asked if the carpenter were to make a similar sandbox TWICE as long, TWICE as wide, and TWICE as high as the first sandbox, what would be the capacity, in cubic feet, of the second sandbox. This question can be solved by TESTing VALUES.

IF... we make the 'starting dimensions' of the sandbox (1 ft.) x (2 ft.) x (5 ft.)....
then the new dimensions (after being doubled) would be: (2 ft.) x (4 ft.) x (10 ft.)
The capacity of the new sandbox would be (2)(4)(10) = 80 cubic feet

Final Answer: D

GMAT assassins aren't born, they're made,
Rich

soniadiana2011 wrote:A carpenter constructed a rectangular sandbox with a
capacity of 10 cubic feet. If the carpenter were to
make a similar sandbox twice as long, twice as wide,
and twice as high as the fi rst sandbox, what would be
the capacity, in cubic feet, of the second sandbox?
(A) 20
(B) 40
(C) 60
(D) 80
(E) 100

We can let the dimensions of the original sandbox be L, W, and H. Thus we have L x W x H = 10 , and the new sandbox would have a capacity of

2L x 2W x 2H = 8 x LWH = 8 x 10 = 80 cubic feet

Answer: D