Question : A person covers a distance of 300 km and then returns to the starting point. The time taken by him for the outward journey is 5 hours more than the time taken for the return journey. If he returned at a speed of 10 km/hr more than the speed of going, what was the speed (in km/hr) for the outward journey?
Option 1: 15
Option 2: 20
Option 3: 30
Option 4: 25
Correct Answer: 20
Solution : Let the speed of the forward journey be $x$ km/hr. Speed of return journey will = $(x + 10)$ km/hr Time taken in return journey = $\frac{300}{(x + 10)}$ hours Time taken in forward journey = $\frac{300}{x}$ hours According to the question, ⇒ $\frac{300}{x} -\frac{300}{x+10} = 5$ ⇒ $\frac{300(x + 10) - 300x}{x(x + 10)} = 5$ ⇒ $300x + 3000 - 300x = 5x^2+50x$ ⇒ $3000 = 5x^2 + 50x$ ⇒ $5x^2 + 50x - 3000 = 0$ ⇒ $x^2 + 10x - 600 = 0$ ⇒ $x^2 + 30x - 20x - 600 = 0$ ⇒ $x(x + 30) - 20(x + 30) = 0$ ⇒ $(x - 20)(x + 30) = 0$ As speed cannot be negative, so $x=20$ km/hr Hence, the correct answer is 20.
Application | Eligibility | Selection Process | Result | Cutoff | Admit Card | Preparation Tips
Question : A person travels a distance of 300 km and then returns to the starting point. The time taken by him for the outward journey is 5 hours more than the time taken for the return journey. If he returns at a speed of 10 km/hr more than the speed of going, what is the average speed (in km/hr) for the entire journey?
Option 1: 20
Option 2: 15
Option 3: 24
Option 4: 30
Question : The speed of a boat in standing water is 6 km/hr and the speed of the stream is 2.5 km/hr. A man rows to a place at a distance of 59.5 kilometres and comes back to the starting point. The total time taken by him is:
Option 1: 16 hours
Option 2: 24 hours
Option 3: 22 hours
Option 4: 18 hours
Question : A man covers a certain distance by bike. If he covers 25% of the distance at the speed of 25 km/hr, 50% of the distance at the speed of 50 km/hr and the remaining distance at the speed of 12.5 km/hr, find his average speed over the whole journey.
Option 1: 20 km/hr
Option 2: 30 km/hr
Option 3: 25 km/hr
Option 4: 35 km/hr
Question : A boy goes from home to school at a speed of 30 km/hr and returns back at a speed of 70 km/hr. What is his average speed for the journey?
Option 1: 42 km/hr
Option 2: 48 km/hr
Option 3: 38 km/hr
Option 4: 36 km/hr
Question : A man runs for 40 km. The time taken by him in the first 10 km is twice the time taken by him in the second 10 km. The time taken in the third 10 km is half of the time taken in the fourth 10 km, and the time taken in the fourth 10 km is equal to the time taken in the first 10 km. If his speed in the first 10 km is 40 km/hr, then what is the average speed for 40 km?
Option 1: 50 km/hr
Option 2: $\frac{70}{3}$ km/hr
Option 3: $\frac{160}{3}$ km/hr
Option 4: $40$ km/hr
Regular exam updates, QnA, Predictors, College Applications & E-books now on your Mobile