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Races and Games

Races and Games - Important Points


1.

In a kilometre race, A beats B by 200 metres or 25 seconds. Speed of B is:

A. 8 m/s

B. 10 m/s

C. 15 m/s

D. 20 m/s

Discuss Work Space

Answer: option a

Explanation:

B completes 200 m in 25 sec. Speed of B = 200 / 25 = 8 m/s.


2.

In a 1.2 km race, A beats B by 150 metres or 30 seconds. Speed of A is:

A. 40/7 m/s

B. 53/7 m/s

C. 67/7 m/s

D. 5 m/s

Discuss Work Space

Answer: option a

Explanation:

Speed of A : Speed of B = 1200 : (1200 - 150) = 8 : 7.

Speed of B = 150 / 30 = 5 m/s.

Speed of A = (8/7) x 5 = 40/7 m/s.


3.

In a 200 m race A beats B by 35 m or 7 seconds. A's time over the course is :

A. 47 sec

B. 40 sec

C. 33 sec

D. 23 sec

Discuss Work Space

Answer: option c

Explanation:

Speed of B = 35/7 = 5 m/s.

Speed of A : Speed of B = 200 : (200 - 35) = 40 : 33.

Speed of A = (40/33) x 5 = 200/33.

Time taken by A = (33/200) x 200 = 33 sec.


4. In a 300 m race Avil beats Bikas by 22.5 m or 6 seconds. Bikas's time over the course is :

A. 86 sec

B. 80 sec

C. 74 sec

D. 70 sec

Discuss Work Space

Answer: option b

Explanation:

Speed of Bikas = 22.5/6 m/s. Time to cover = 300 / (22.5/6) = 80 secs.

5. In a 100 m race, Akash covers the distance in 36 seconds and Biswas in 45 seconds. In this race Akash beats Biswas by:

A. 9 m

B. 25 m

C. 22.5 m

D. 20 m

Discuss Work Space

Answer: option d

Explanation:

Distance covered by Biswas in 36 secs = (100/45) x 36 = 80 m. So, Akash beats Biswas by 20 m.