This one’s a DS question about unit conversion and time , how do you know if it’s enough without calculating everything?

Question

A tank containing water started to leak. Did the tank contain more than 30 gallons of water when it started to leak? (Note: 1 gallon = 128 ounces)

1. The water leaked from the tank at a constant rate of 6.4 ounces per minute.

2. The tank became empty less than 12 hours after it started to leak

Mohit C · Accepted Answer

For DS questions involving units and time, the goal isn&rsquo;t always to compute, just to check if a unique answer is possible.
Statement 1 gives a leak rate of 6.4 ounces per minute. But without knowing how long the tank leaked, we can&rsquo;t say how much water was originally in it. The leak could&rsquo;ve lasted 2 hours or 20 &mdash; so this alone isn&rsquo;t sufficient.
Statement 2 says the tank emptied in less than 12 hours. But that tells us nothing about the leak rate. A tank with just 1 gallon could empty in under 12 hours if the leak is slow, or a large tank could also empty in under 12 hours if the leak is fast. So this too is not sufficient.
Even when you combine both, all you get is a maximum possible volume &mdash; the tank could have held less than 36 gallons, but it might have been just 10 or 31. That uncertainty means you still can&rsquo;t tell whether it held more than 30 gallons. Final answer: E.

Divakshi Arora · Answer

Here&rsquo;s how to decide without doing full calculations:

Statement 1 gives the leak rate of 6.4 ounces per minute, but without knowing how long the leak lasted, we can&rsquo;t determine how much water was in the tank. Not sufficient.
Statement 2 tells us the tank emptied in less than 12 hours, but without knowing the leak rate, we can&rsquo;t calculate the total volume. Not sufficient.
Combining both, the max leak time is 12 hours, and the rate is 6.4 oz/min, which totals about 36 gallons.But since it says &ldquo;less than&rdquo; 12 hours, the actual amount could be less &mdash; possibly below 30 gallons.
So even together, the information doesn&rsquo;t guarantee whether the tank held more than 30 gallons.

Answer is E,  not sufficient.