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


70 km/hr
75 km/hr
84 km/hr
87.5 km/hr


Answer

 Option

Let the speeds of two trains be 7x and 8x km/hr. then 8x = 400/4 = x = 100/8 = 12.5 speed of first train = (7*12.5 = 87.5 km/hr

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42.  A truck covers a distance of 550 meters in 1 minutes whereas a bus covers a distance of 33 kilometers in 45 minutes. The ratio of their speeds is?


3:4
4:3
3:5
50:3


Answer

 Option

Ratio of speeds = (550/60*18/5) :(33/45*60) = 33:44 = 3:4.

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43.  one of the two buses completes a journey of 300 km in 7 1/2 hours and the other a journey of 450 km in 9 hours. the ratio of their average speeds is?


2:3
3:4
4:5
8:9


Answer

 Option

Ratio of speeds = (300*2/15) : (450/9) = 40: 50 = 4:5.

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44.  A car is running at a speed of 108 km. What distance will it cover in 15 seconds?


45 meters
55 meters
450 meters
none of these


Answer

 Option

Speed = 108 km = (108*5/18) m/sec = 30 m/sec. therefore distance covered in 15 sec. = (30*15) m = 450 m.

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45.  How long will a boy take to run round a square field of side 35 meters, if he runs at the rate of 9 km/hr?


50 sec
52 sec
54 sec
56 sec


Answer

 Option

Speed = 9 km/hr = (9* 5/18) m/sec = 5/2 m/sec. distance = (35*4) m = 140m. therefore time taken =(140*2/5) sec = 56 sec.

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