Jack has full tank of gas in his car and wants to drive 550 miles. He

Jack has full tank of gas in his car and wants to drive 550 miles. He doesn’t remember the capacity (in gallons) of his gas tank nor does he remember his car's fuel efficiency. If Jack travels at a constant speed, does he have enough gas to drive to his destination?

Total tank capacity = X

f) After he drives 137 miles he realizes he has three-quarters of the full tank of gas left.
After 137 miles, he consumed 25% of fuel, remaining 3X/4 fuel. So, 137 *4 =548 miles, he can be drive 548 miles. So, he's short of 2 miles fuel. So he did not have enough gas to drive to destination. Confirmed yes answer. Sufficient.

2) After he drives 411 miles he realizes he has used three-quarters of the full tank of gas.
After 411 miles, he used 75 % of fuel, remaining X/4 of fuel. So, 3X/4 fuel covers 411 miles, So, 137 miles more he can travel. Again, he's short of 2 miles fuel. So he did not have enough gas to drive to destination. Confirmed yes answer. Sufficient.

Imo. D

Jack has full tank of gas in his car and wants to drive 550 miles.

To drive whether Jack will be able to drive 550 miles with his current tank capacity. We need know his tank capacity and also fuel efficiency.

1) After he drives 137 miles he realizes he has three-quarters of the full tank of gas left.

We now know that he was able to drive 137 miles with 25% of his gas capacity. So with his full tank , he can drive 137*4 = 548 miles.

Option 1 is Sufficient.

2) After he drives 411 miles he realizes he has used three-quarters of the full tank of gas.

We now know that Jack has driven 411 miles with 75% of his tank. So we can calculate that with 100% of tank capacity, he could drive - 411 * (4/3) = 548 Miles.

Option 2 is Sufficient.

Ans: D

OA is D. Either statement alone is sufficient.

Statement 1: he drove 137 miles using 1/4 of full tank. So he will be able to drive 137*4=548 miles with the remaining fuel. So he won't be able to reach it's destination with the fuel.(sufficient)
Statement 2: he drove 411 miles using 3/4 gallons of fuel that means he will reach only 411/3*4 miles=548 with the fuel tank. Which is again not enough to reach its destination.
(Sufficient)
So OA is D

Posted from my mobile device

Given:
1. Jack has full tank of gas in his car and wants to drive 550 miles.
2. He doesn’t remember the capacity (in gallons) of his gas tank nor does he remember his car's fuel efficiency.

Asked: If Jack travels at a constant speed, does he have enough gas to drive to his destination?

f) After he drives 137 miles he realizes he has three-quarters of the full tank of gas left.
1/4 of full tank of gas is consumed to travel 137 miles
1 full tank of gas will be consumed to travel 137 * 4 = 548 miles
He does not have enough gas to travel 550 miles
SUFFICIENT

2) After he drives 411 miles he realizes he has used three-quarters of the full tank of gas.
3/4 of full tank of gas is consumed to travel 411 miles
1 full tank of gas will be consumed to travel 411 * 4/3 = 548 miles
He does not have enough gas to travel 550 miles
SUFFICIENT

IMO D

Answer : D
Statement:1
for 137 miles ,1/4 of tank used (V/4)
correspondingly for balance 413 miles ,gas needed to drive= V/4X413/137=Approx 3/4V ,which is available
Sufficient
Statement 2:
For 411 miles,3/4 of tank used(3/4V)
Correspondingly, for balance 139 miles ,gas needed to drive=3V/4X139/411=Apprx. V/4,which is available
Sufficient
`

Let capacity of tank be g. We need to find if g gallons of gas is sufficient to drive 550 miles

Statement 1: Dist. = 137 miles, Gas used = \(\frac{1}{4}\)g gallons
so distance covered in g gallons or 1 full tank = 137*4=548 miles

Sufficient

Statement 2: Dist. = 411 miles, Gas used = \(\frac{3}{4}\)g gallons
so distance covered in g gallons or 1 full tank = 411*4/3=548 miles
Sufficient

Answer = D

Assumption is that he is getting constant mileage.

1) After he drives 137 miles he realizes he has three-quarters of the full tank of gas left.

So he covered 137miles in 1/4th of a tank and will be able to cover 411 miles with remaining 3/4th. Sufficient to answer the question.

2) After he drives 411 miles he realizes he has used three-quarters of the full tank of gas.
Exact opposite of what is given in Statement 1 but the same numbers. Sufficient to answer.

Answer D

QQ:- is it recommended to assume an initial capacity in these types of question? how I worked on this one was simply assuming 100 G as the full capacity of the car which made the picture clear at every step while doing cal. and I still came to the right answer.

thanks in advance.

Solution:-

St(1):-After he drives 137 miles he realizes he has three-quarters of the full tank of gas left

=>1/4 of full tank of gas is consumed to travel 137 miles

=>Remaining is 3/4 th of tank

=>Since he is driving at a constant speed,

=>137 *4 =548 miles,

=>He can be drive 548 miles.

=>He is short of fuel for 2 miles

=>He did not have enough gas to drive to destination. (Sufficient)

St(2):-After he drives 411 miles he realizes he has used three-quarters of the full tank of gas.

=>With 3/4 th of the tank, 411 miles has been travelled

Since, he is driving at a constant speed

=>He can travel 137 miles more (Since, 411 * (4/3) = 548miles)

=>He is short of fuel for 2 miles

=>He did not have enough gas to drive to destination.(sufficient) (option d)

Devmitra Sen
GMAT SME

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