Arithmatical -Time and Distance

DIRECTIONS : Problems based on time and distance.
1. An express train travelled at an average speed of 100 km/hr, stopping for 3 minutes after every 75 km. How long did it take to reach its destination 600 km from the starting point?
  A.  6 hrs 21 min
  B.   6 hrs 24 min
  C.  6 hrs 27 min
  D.  6 hrs 30 min
Solution
Time taken to cover 600 km= (600/100)hrs
=6 hrs.
Number of stoppages= 600/75 - 1
=7.
Total Time of stoppages= (3 x 7)min
=21 min.
Hence,total time taken=6 hrs 21 min.
2. Sound is said to travel in air at about 1100 feet per second. A man hears the axe striking the tree, 11/5 seconds after he sees it strike the tree. How far is the man from the wood chopper?
  A.  2197 ft
  B.  2420 ft
  C.  2500 ft
  D.  2629 ft
Solution
Distance= (1100 x 11/5)feet
= 2420 feet.

3. The speed of a car increases by 2 kms after every one hour. If the distance travelling in the first one hour was 35 kms. what was the total distance travelled in 12 hours?
  A.  456 kms
  B.  482 kms
  C.  552 kms
  D.  556 kms
Solution
Total distance travelled in 12 hours =(35+37+39+.....upto 12 terms)
This is an A.P with first term, a=35, number of terms,
n= 12,d=2.
Required distance= 12/2[2 x 35+{12-1) x 2]
=6(70+23)
= 552 kms.
4. A person croses a 600 m long street in 5 minutes. What is his speed in km per hour?
  A.  3.6
  B.  7.2
  C.  8.4
  D.  10
Solution
Speed =(600 / 5 x 60)m/sec
= 2 m/sec
=(2 x 18/5)km/hr
= 7.2 km/hr.
5. A train travels at an average of 50 miles per hour for 2x1/2 hours and then travels at a speed of 70 miles per hour for 1x1/2 hours. How far did the train travels in the entire 4 hours?
  A.  120 miles
  B.  150 miles
  C.  200 miles
  D.  230 miles
Solution
Total distance travelled = [(50 x 2x1/2)+(70x1x1/2)]
= (125+105)miles
= 230miles.
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