a layer of mulch

[sanju09]

A rectangular garden that is 10 feet long and 5 feet wide is to be covered with a layer of mulch 0.5 foot deep. At which store, K or L, will the cost of the necessary amount of mulch be less?

(1) Store K sells mulch only in bags, each of which costs $7 and contains 6.25 cubic feet of mulch.

(2) Store L sells mulch only in bags, each of which costs $40 and contains 25 cubic feet of mulch.


[spoiler]Source: https://gmat.practicetests.teachstreet.com[/spoiler]

[niksworth]

IMO C.

Volume of mulch required = 10 x 5 x 0.5 = 25 cubic feet.

From statement 1, cost per cubic feet of mulch in store K = 7/6.25 = $1.12
From statement 2, cost per cubic feet of mulch in store L = 40/25 = $1.6

To serve the purpose we would have to buy 4 bags from store K with total price of $28 or 1 bag from store L with total price of $40. Clearly K is much cheaper.

To arrive at this conclusion, we need both statements 1 and 2 together, none of the statements in isolation will provide the answer.

OA please.

[Maciek]

Hi!

IMO C

let us first calculate what is the necessary amount of mulch

it is rectangular box so formula for the volume is

V = area of the base * Height

V = (10 * 5) * 0.5 = 25 cubic feet

the necessary amount of mulch is V = 25 cubic feet

(1) Store K sells mulch only in bags, each of which costs $7 and contains 6.25 cubic feet of mulch.

this statement ALONE is INSUFFICIENT because there is only information about store K

(2) Store L sells mulch only in bags, each of which costs $40 and contains 25 cubic feet of mulch.

this statement ALONE is INSUFFICIENT because there is only information about store L

the answer must be C or E

(1) & (2)

what is the cost of the necessary amount of mulch?

Store K:

one bag costs $7 and contains 6.25 cubic feet of mulch

V = 25

V/ 6.25 = 25/6.25 = 4

the cost of the necessary amount of mulch is

4 * $7 = $28

Store L:

one bag costs $40 and contains 25 cubic feet of mulch

the necessary amount of mulch is 25 so the cost is $40

The cost of the necessary amount of mulch will be less at store K

answer is C

Hope it helps!

Best,
Maciek