Quiz Discussion

A person can row \(7\frac{1}{2}\) km an hour in still water. Finds that it takes twice the time to row upstream than the time to row downstream. The speed of the stream is:

• 1] 2 kmph
• 2] 2.5 kmph
• 3] 3 kmph
• 4] 4 kmph

Karan and Arjun run a 100 metre race, where Karan beats Arjun by 10 metre. To do a favour to Arjun, Karan starts 10 metre behind the starting line in a second 100 race. They both run at their earlier speeds. Which of the following is true in connection with the race?

• 1] Karan and Arjun reach the finishing line simultaneously
• 2] Arjun beats Karan by 1 metre
• 3] Arjun beats Karan by 11 metre
• 4] Karan beats Arjun by 1 metre
• 5] Cannot be said

A car goes 20 metres in a second. Find its speed in km/hr.

• 1] 20 km/hr
• 2] 18 km/hr
• 3] 72 km/hr
• 4] 36 km/hr

A is twice fast as B and B is thrice fast as C is. The journey covered by C in \(\frac{3}{2}\) hours will be covered by A is:

• 1] 15 minutes
• 2] 20 minutes
• 3] 30 minutes
• 4] 1 hour

A car traveling with \(\frac{5}{7}\) of its usual speed covers 42 km in 1 hr 40 min 48 sec. What is the usual speed of the car?

• 1]

  \(17\frac{6}{7}\) km/hr

• 2]

  35 km/hr

• 3]

  25 km/hr

• 4]

  30 km/hr

A person can row a boat d km upstream and the same distance downstream in 5 hours 15 minutes. Also, he can row the boat 2d km upstream in 7 hours. How long will it take to row the same distance 2d km downstream?

• 1]

  \(\frac{{3}}{{2}}\) hours

• 2]

  7 hours

• 3]

  \(\frac{{29}}{{4}}\) hours

• 4]

  \(\frac{{7}}{{2}}\) hours

A is twice fast as B and B is thrice fast as C. The journey covered by C in 78 minutes will be covered by A in :

• 1] 13 min
• 2] 15.5 min
• 3] 17 min
• 4] 12 min

A 6 × 6 grid is cut from an 8 × 8 chessboard. In how many ways can we put two identical coins, one on the black square and one on a white square on the grid, such that they are not placed in the same row or in the same column?

• 1] 216 ways
• 2] 324 ways
• 3] 144 ways
• 4] 108 ways

A cyclist moving on a circular track of radius 100 meters completes one revolution in 2 minutes. What is the average speed of cyclist (approx.)?

• 1] 314 m/min
• 2] 200 m/min
• 3] 300 m/min
• 4] 900 m/min
• 5] None of these

A candle of 6 cm long burns at the rate of 5 cm in 5 hour and an another candle 8 cm long burns at the rate of 6 cm in 4h. What is the time required to each candle to remain of equal lengths after burning for some hours, when they starts to burn simultaneously with uniform rate of burning?

• 1] 1 hours
• 2] 1.5 hours
• 3] 2 hours
• 4] 3 hours
• 5] 4 hours