gmat prep PS

nov 2
dec 2
jan 2
feb 2

mar 1 (0.7)
ape 1 (0.6)
may 1 (0.5)
jun 1 (0.4)
jul 1 (0.3)
aug 1 (0.2)
sep 1 (0.1)
oct 1

2 2.8
1 1.4

IMO C

Here is how I approached the problem.

total rake produced from Nov to Feb is 4X.

There are eight months wherein at the beginning of the month X/2 rakes are shipped
We can represent it as below :

Month...........: 1----2----3----4----5----6----7----8
Rakes stored : -----3X--------2X---------X---------0

If you notice, the business need to pay only on the first 7 months because there is no rakes left in the 8th month.
Another important thing to notice is the average number of rakes stored per month is 2X.

So, total storage cost in dollars,

= 7(2X)(0.1) = 1.4X

Hope this helps

-Shaz

I am not clear about the average number of rakes stored per month.

How are u getting that as 2X

The best way to solve this type of question is based on assumption which Suyog had adopted...Thats the best approach to find the right ans..esp when you are running out of time...

Another explanation is as follows

Rakes produced from nov to feb is given by 4x

It is given in the question that x/2 rakes are shipped at the beginning of each month starting from march and the storage amt for each rake is 0.1$..

so if x/2 rakes are shipped in march...storage amt for remaining rakes=(4x-x/2)0.1=0.35x$
storage amt for april=(4x-x)0.1=0.3x$
storage amt for may (4x-3x/2)=0.25x$
storage amt for june =0.2x$
.......................july=0.15x$
...................august=0.1x$
.............september=0.05x$
...............october = 0$ (since there are no rakes left)

total storage cost= (.35+.3+.25+.2+.15+.1+.05)x= 1.4x

Hope this explanation helps...

Is there any other shorter method to do this.

I was able to do step by step procedure b ut it takes more than 2 minutes.

If I take X=10 then my total storage inventory works out to be 140x which is 140*0.1 = 14 x.

Ok Apologize for putting lot of questions and answers on this one: Must be a simple problem for people, but I just wanted to come up with a quicker method that takes less than 1.5 minutes. Here's the solution:

Assume that 10 Rakes are produced each month from Nov to feb. Athe begininnig of March there are 40 Rakes

March: 40-5= 35 ( I get 5 from 10/2 or x/2)
April:30
May: 25
June: 20
July: 15
August: 10
Sept: 5
October: 0


Total = 140 stored
If 4 rakes are produced then 140 rakes are stored each month

for 1 rake: 14 rakes stored

14 x* $0.1 = 1.4

Try with any number of rakes produced. You will get this answer.