vinay1983 wrote:How long did the 1000 mile journey with 10 stopovers take Mr. X?
1. The ith stopover lasted i^2 minutes
2. The average speed between any 2 stopovers was 66 miles per hour.
Target question: How long did the 1000 mile journey with 10 stopovers take Mr. X?
IMPORTANT: The total time to complete the journey = (
total driving time) + (
total stopover time)
Statement 1: The ith stopover lasted i^2 minutes
In other words, the 1st stopover lasted 1 minute, the 2nd stopover lasted 4 minutes, the 3rd stopover lasted 9 minutes, the 4th stopover lasted 16 minutes, etc.
We can use this to find the
total stopover time for all 10 stops.
HOWEVER, there's no way we can determine the
total driving time.
Since we cannot answer the
target question with certainty, statement 1 is NOT SUFFICIENT
Statement 2: The average speed between any 2 stopovers was 66 miles per hour.
Total driving time = distance/(average speed)
= 1000/66 hours
So, here we can determine the
total driving time.
HOWEVER, there's no way we can determine the
total stopover time
Since we cannot answer the
target question with certainty, statement 2 is NOT SUFFICIENT
Statements 1 and 2 combined
Statement 1 tells us the total stopover time
Statement 2 tells us the total driving time
So, we can now answer the
target question with certainty.
The combined statements are SUFFICIENT, and the correct answer is
C
Cheers,
Brent
