Quiz Discussion

A 6 cm long cigarette burns up in 15 minutes if no puff is taken.For every puff, it burns three times as fast during the duration of the puff.If the cigarette burns itself in 13 minutes, then how many puffs has the smoker taken if the average puff lasted 3 seconds?

• 1] 17
• 2] 18
• 3] 20
• 4] 22
• 5] None of these

Walking \(\frac{3}{4}\) of his normal speed, Rabi is 16 minutes late in reaching his office. The usual time is taken by him to cover the distance between his home and office:

• 1] 48 min.
• 2] 60 min.
• 3] 42 min.
• 4] 62 min.
• 5] 66 min.

A man performs \(\frac{2}{15}\) of the total journey by rail, \(\frac{9}{20}\) by bus and the remaining 10 km, on the cycle. His total journey is :

• 1] 31.2 km
• 2] 38.4 km
• 3] 32.8 km
• 4] 24 km

The ratio between the speeds of two trains is 7 : 8. If the second train runs 400 km in 4 hours, then the speed of the first train is:

• 1] 70 km/hr
• 2] 75 km/hr
• 3] 84 km/hr
• 4] 87.5 km/hr

A train travels at a speed of 30 km/hr for 12 minutes and at a speed of 45 km/hr for the next 8 minutes. The average speed of the train for this journey is :

• 1] 30 km/hr
• 2] 36 km/hr
• 3] 37.5 km/hr
• 4] 48 km/hr

An aeroplane covers a certain distance at a speed of 240 kmph in 5 hours. To cover the same distance in \(1\frac{2}{3}\) hours, it must travel at a speed of :

• 1] 300 kmph
• 2] 360 kmph
• 3] 600 kmph
• 4] 720 kmph

Two trains 150 m and 120 m long respectively moving from opposite direction cross each other in 10 sec. If the speed of the second train is 43.2 km/hr, then the speed of the first train is :

• 1] 54 km/hr
• 2] 50 km/hr
• 3] 52 km/hr
• 4] 51 km/hr

A train 300 m long is running with a speed of 54 km/hr. In what time it cross a telephone pole ?

• 1] 20 seconds
• 2] 15 seconds
• 3] 17 seconds
• 4] 18 seconds

A ship leaves on a long voyage. When it is 18 miles from shore, a sea plane, whose speed is ten times that of the ship, is sent to deliver mail. How far from the shore does the sea plane catch up with the ship?

• 1] 24 miles
• 2] 25 miles
• 3] 22 miles
• 4] 20 miles
• 5] None of these

Running at \(\frac{5}{4}\) of his usual speed, an athlete improves his timing by 5 minutes. The time he usually takes to run the same distance is:

• 1] 30 min.
• 2] 28 min.
• 3] 25 min.
• 4] 23 min.