1. A man starts from a place P and reaches the place Q in 7 hours. He travels 1/4 th of the distance at 10 km/hour and the remaining distance at 12 km/hour. The distance, in kilometer, between P and Q is:
A. 70 km
B. 72 km
C. 80 km
D. 90 km
Answer: Option C
Explanation: Let one-fourth of the distance between P and Q be x km
then
Time taken for the first one-fourth distance = [latex]\frac{×}{10}[/latex] km/hour
and
Time taken for the remaining distance = [latex]\frac{2×}{12}[/latex] km/hour
Since Total time taken is 7 hours ⇒ 7 = [latex]\frac{×}{10}[/latex] + [latex]\frac{3×}{12}[/latex]
On solving, x = 20
Total distance = 4x = 80 km.
2. In the school, Mohan and Govind took a part in the race and the ratio between their speeds is 5 : 7. Mohan losses the race by 360m then what is the length of the track (in km)?
A. 1.26 km
B. 1.2 km
C. 2 km
D. 0.9 km
Answer: Option A
Explanation: t = [latex]\frac{D}{S}[/latex]
According to the question,
Let Speed = 5x, 7x Distance = y m
[latex]\frac{y - 360}{5×}[/latex] = [latex]\frac{y }{7×}[/latex]
[latex]\frac{y - 360}{5}[/latex] = [latex]\frac{y }{7}[/latex]
7 (y – 360) = 5y
7y – 5y = 2520
2y = 2520
y = 1260
= 1.26 km.
3. The respective ratio between the speed of a car, a train, and a bus is 5 : 9 : 4.The average speed of the car , the bus and the train is 72 km/hr together. What is the average speed of the car and the train together?
A. 82 km/h
B. 72 km/h
C. 84 km/h
D. 67 km/h
Answer: Option C
Explanation:Let speed of the car, the train, and the bus be 5a Km/hr , 9a Km/hr and 4a Km/hr respectively.
Given, total speed = (72 × 3) Km/hr = 216 Km/hr
⇒ 5a + 9a + 4a = 216
⇒ 18a = 216
⇒ a = 12Km/hr
⇒ speed of car = 5 × 12 = 60 Km/hr
And
speed of train = 9 × 12 = 108 Km/hr
⇒ their average speed = [latex]\frac{60 + 108}{2} [/latex] = 84 Km/hr
4. Ranvir goes to his office from his house at a speed of 16 km/hr and returns to his home from his office at a speed of 20 km/hr and he takes 4 hour 30 minutes in all. If the distance of his friend's house from his office is 20% more than the distance of his house from his office, find the distance of his house to his friend's house.(assuming the office lies between Ranvir's house and his friend's house)
A. 80 km
B. 60 km
C. 92 km
D. 88 km
Answer: Option D
Explanation: Let the distance of his house to his office = D km
T = [latex]\frac{D}{S}[/latex]
4 hour 30 minutes =[latex]\frac{D}{16}[/latex]+[latex]\frac{D}{20}[/latex]
[latex]\frac{9}{2}[/latex] = [latex]\frac{5D + 4D}{80}[/latex]
[latex]\frac{9}{2}[/latex] = [latex]\frac{9D}{80}[/latex]
D = 40
The distance from his house to his office = 40 km
The distance from his office to his friend's house = 40 km × 120% = 48 km
The distance from his house to his friend's house = 40 + 48 = 88 km
5. Mohit and Anuj took a part in a race. Mohit runs 300m in 50 second and Anuj takes 1 minute to cover the same distance. By what distance will Mohit beat Anuj in 300 m race?
A. 25 m
B. 55 m
C. 60 m
D. 50 m
Answer: Option D
Explanation: Mohit runs 300m in 50 sec.
Anuj runs 300m in 60 sec.
Now, In 1 sec Anuj runs 5m
Therefore, in 50 sec Anuj runs 50×5 = 250m
Mohit beats Anuj by 300 - 250 = 50m