I14-08

Question

https://gmatclub.com/gmat-focus-tests/resources/import/img/I14-08.png 
 
A company uses pipelines to transfer fuel to different departments in the company. The flowchart above shows the movement of fuel from the main source A to different departments shown by the alphabets B to I. The requirements of each department are indicated by a number above the department's name. The fuel is transferred only once a day as per the combined requirement of the departments and the direction is shown by the arrow. The remaining fuel moves ahead only after meeting the requirement of a particular department. The maximum capacity of a single pipeline is 700 liters.
 
For example, if 500 liters move from A to C, then 150 liters is left in C to fulfill its requirement, and the remaining 350 liters move from C to E.
 
From each drop down menu, select the option that creates the most accurate statement based on the information given.

If the entire requirement of all departments is met, then  GRAPH_1_PLACEHOLDER  liters of fuel flows in the pipeline EH, and  GRAPH_2_PLACEHOLDER  liters of fuel flows out from the main source A.

Bunuel · Answer

Official Solution:

Drop-downs 1 and 2: 
 
First, let's determine the total requirement of all departments. Summing up each department's requirements, we get  a total of 1,400 liters . Since the maximum capacity of a single pipeline is 700 liters, meeting the requirements of all departments will require 700 liters flowing from A to C and another 700 liters flowing from A to B. 
 
The combined requirement of departments C, E, and F is  150 + 180 + 170 = 500  liters. Therefore, out of the initial 700 liters flowing from A to C,  700 - 500 = 200  liters will remain to be transferred from E to H, compensating for the missing volume needed in the lower part of the flowchart.

Correct answer:

Dropdown 1:  "200"

Dropdown 2:  "1400"

Bunuel · Answer

I have revised the question, solution, and formatting by adding more details to enhance clarity.

A_ · Answer

I like the solution - it’s helpful.

Sushi_545 · Answer

hI  Bunuel ,

can you please let me know why we have divided and assumed 700 too be equally divided?

Bunuel · Answer

Where do you see 700 liters to be equally divided?

The  700-liter limit  is the  maximum capacity  of any one pipeline. Since the  total requirement  is 1,400 liters and  no single pipe can carry more than 700 , the company must  send 700 liters on each route from A :

700 from A to B 
 700 from A to C

This is the  only way  to meet the full 1,400-liter demand without exceeding pipeline limits. So it’s not an equal split by assumption, it’s a  necessity based on the 700-liter cap per pipeline .

Sushi_545 · Answer

hi  Bunuel ,

ok thanks got this was too silly not to think about this.

srik410 · Answer

The OA is absolutely crisp. However, I am adding an alternative way to solve this.

By identifying the bottlenecks.  
If you take a overall look, there is really one bottleneck at H. Why? Because 700 limit is quite high and you can add you the requirements before this without any problem. 
So, this problems reduces to "what happens to before and after H?"

Outflow at H -> 190+150=340
This should be divided among EH and GH but how?

Lets see how much AC and AB handle without supplying to H. We have 150+180+170(from upper part) + 120+240+200(from lower part)
-> ie 500(from upper part) + 560(from lower part)

We have a 700 limit for each AC as well as AB, but you need to divide 340 into (from upper part) and (from lower part)
The max upper can handle is 200 more and lower can handle is 140 more. But this is indeed the requirement at H.

So they have to both work at full capacity to allow this. So, EH=200 and GH=140

alrightalright · Answer

I like the solution - it’s helpful.

BinodBhai · Answer

This is a great question that’s helpful for learning.

GMAT1034 · Answer

In EH question why are we assuming that min amount of fuel only will flow via these 3, if there had been more amount of fuel flowing the answer would have been less than 200. Could you please clarify?  Bunuel

Bunuel · Answer

The flow is fixed at 200 because the pipeline from A to C carries its maximum of 700 liters. Departments C, E, and F together consume exactly 500, and since their requirements are capped, they cannot take more. That leaves exactly 200 to continue through EH.

Karym · Answer

I like the solution - it’s helpful.

Karym · Answer

I like the solution - it’s helpful.

PurvaG · Answer

why have we assume that the fuel moves from E TO F instead directly from E to H

Bunuel · Answer

Because F can get fuel only from E. So if the entire requirement of all departments is met, 170 liters must go from E to F, and only the remaining fuel from that branch can go from E to H.

We are not assuming all fuel goes to F first. We are only using the fact that F has no other source.

I14-08

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