Is assumption required in GMAT?--Can the MGMAT Experts Comme

[Saurabh Malpani]

Hello The following question is from GMATCLUB TEST 15

Two engines were put to test to determine their fuel consumption rate. During the test the first engine consumed 600 grams of fuel while the second, which worked for two hours less, consumed 384 grams. How much fuel will be required to run the second engine for 5 hours?

a) The first engine worked for 10 hours during the test
b) If the first engine had worked for 2 more hours during the test, it would have consumed 120 grams of fuel more

Well The question says Fuel Consumption Rate ---The question can mean that rate is constate w.r.t time or the rate differs with respect to time.


For e.g a Machine consume more Energy as soon as it's started but as it reaches a Particular torque and mainted the rate of consumption will become constant (Rate differs with Time)--Answer E

Or we can assume that right from start of the engine the rate is constant--Result in Answer D

So based on the assumption the asnwer can be D/E.

I know it's not a real GMAT Question but can we encounter such questions?

Or am I thinking too much about the question?

Saurabh Malpani

[raja_asu]

I think u r going into too much detail of how engine works. Maybe for these type of question, we should always step back and see if everyone irrespective of their educational background have the same information or assumption as we do.

Rajesh

[Guest]

Yeah, like me for instance. :-) I'm studying for the exam and definitely have no background of how engines work, so I would have never guessed that an engine consumes more fuel when started up. Since this is something not all people taking the exam probably know and it is outside the realm of Verbal and Quant, it cannot be expected to be known on the exam.

[StaceyKoprince]

The official test:
(a) never assumes you know anything other than what's stated for CR and RC, and
(b) would tell you explicitly on a problem like this one that the fuel is consumed uniformly (or something along those lines)

[guest]

These work/rate problems on the GMAT are always nice and linear. Machines knock at widgets at a constant rate, workers don't take coffee breaks, etc. And more resources always causes productivity to improve linearly.

I've often thought harder, non-linear, work rate problems might be the Next Big Thing on the GMAT once everyone starts coming in well prepped for the number theory and probability problems.