#2. An engine used up fuel

[nirbhik.modi87]

#2. An engine used up fuel at a constant rate
until it ran out of fuel. At what time did the
engine run out of fuel?

(1) At 1:00 P.M., the engine had 2/3 more
fuel than it had at 5:00 P.M.

(2) At 1:00 P.M., the engine had 6 more
liters of fuel than it had at 5:00 P.M

Source: Question # 2 , MGMAT Class Handout # Session 2.

I am not able to understand why is 2 insufficient.

For option 1, I just assumed a random amout of fuel. And I tried using the same strategy for 2'nd question. I am confused with the explanation provided in handout.

if possible please explain in more simpler terms.

Thanks,
Nirbhik Modi

[RonPurewal]

It seems you don't yet understand what DS is fundamentally about.

The point of DS is to decide whether...
... there is only one solution to the question
OR
... there is more than one solution to the question.

This is the whole point of DS. Make sure you think carefully and concretely about this goal before diving headfirst into the problems.

For option 1, I just assumed a random amout of fuel. And I tried using the same strategy for 2'nd question.

Note the goal above. You have to find out whether multiple solutions are possible.

If you just assume ONE amount of fuel, then of course you're just going to get one answer. And that means nothing.
(In fact, if you take this approach"”just plugging in one specific case and then deciding you're finished"”you're going to think that EVERY statement is ALWAYS "sufficient".)

When you "plug in values" on DS, you MUST TRY MULTIPLE VALUES. That's the only way you can tell whether multiple solutions are possible.

"- If you plug in multiple values and all of them give the same answer"”and you become convinced that you're going to get the same answer every time (or you run out of cases to plug in)"”then that's "sufficient".

- If you ever get two different answers from plugging in different cases, that's "not sufficient".