tgsankar10
Bunuel
sumitsingh18
I think this is a high-quality question and I don't agree with the explanation. While solving 1st option , total time is not mentioned. Therefore, how can we calculate the average speed for the entire journey??
From (1) we know that in 1 hour the bus finished
1/3 of the distance at an average speed of 60 kilometers per hour. This implies that 60 kilometers is
1/3 of the distance, so the total distance is 180 kilometers.
BunuelThis is the question I'm seeing:
If a bus took three hours to travel from town A to town B, what was its average speed throughout the entire journey?The question asks for
average speed of entire journey. But your answer and explanation is about
finding the total distance of the journey. There seems to be some confusion in the question & explanation. Please clarify.
Please re-read the very first sentrence of the solution:
If a bus took three hours to travel from town A to town B, what was its average speed throughout the entire journey?To find the average speed, we use the formula: \(\text{Average speed}=\frac{\text{total distance}}{\text{total time}}\). We know the total time is 3 hours, so we need to determine the total distance.(1) In the first hour, the bus covered \(\frac{1}{3}\) of the total distance at an average speed of 60 kilometers per hour.
Since \(\frac{1}{3}\) of the distance is \(1*60=60\) kilometers, the total distance is \(3*60=180\) kilometers. This statement is sufficient.
(2) During the second hour, the bus had an average speed of 80 kilometers per hour, which is double its speed in the third hour.
During the second hour, the bus covered 80 kilometers, and during the third hour, the bus covered \(\frac{80}{2}=40\) kilometers. Thus, in the last two hours, it covered a total of 120 kilometers. However, we don't know how many kilometers were covered during the first hour, so this statement is not sufficient.
Answer: A