100+ Speed, Time and Distance Questions and Answers Pdf - 1

Question: 1

Suriya rides her bike at an average speed of 30 km/hr and reaches her destination in 6 hours. Suganya covers the same distance in 4 hours. If Suriya increases her average speed by 10 km/hr and Suganya increases her average speed by 5 km/hr, what would be the difference in their time taken to reach the destination?

(A) 40 minutes

(B) 42 minutes

(C) 47 minutes

(D) 54 minutes

Ans: D

Suriya’s original speed = 30 km/hr.

Suriya’s new speed = (30 + 10) km/hr = 40 km/hr.

Distance = (30 × 6) km = 180 km.

Suganya’s original speed = $$({180} / {4})$$km/hr = 45 km/hr.

Suganya’s new speed = (45 + 5) km/hr = 50 km/hr.

Difference in time = $$({180} / {40} – {180} /{50})$$hrs

                          = $${9}/{10}$$ hrs = $$({9}/{10} × 60)$$min = 54 min.

Question: 2

A train covers a distance of 10 km in 12 minutes. If its speed is decreased by 5 km/hr, the time taken by it to cover the same distance will be

(A) 10 min

(B) 13 min

(C) 13 min 20 sec

(D) 14 min

Ans: C

Speed = $$(10 × {60}/{12})$$km/hr = 50 km/hr.

New speed = (50 – 5) km/hr = 45 km/hr.

∴ Time taken = $$({10}/{45})$$ hr

                    = $$({2}/{9} × 60)$$ min = $$13{1}/{3}$$min. = 13 min 20 sec.

Question: 3

A boy rides his bicycle 10 km at an average speed of 12 km/hr and again travels 12 km at an average speed of 10 km/hr. His average speed for the entire trip is approximately.

(A) 10.4 km/hr

(B) 10.8 km/hr

(C) 11 km/hr

(D) 12.2 km/hr

Ans: B

Total distance travelled = (10 + 12) km/hr = 22 km/hr.

Total time taken = $$({10}/{12} + {12}/{10})$$ hrs = $${61}/{30}$$ hrs.

∴ Average speed = $$(22 × {30}/{61})$$ km/hr = 10.8 km/hr.

Question: 4

An athlete claimed that his timing for a 100 m dash should be corrected because the starting signal was given by a gun fired from a point 10 m away from him and the timekeeper was standing close to the gun. The error due to this could be (in seconds).

(A) 0.3

(B) 0.03

(C) 0.5

(D) 0.7

Ans: B

Error = Time taken to cover 10 m at 300 m/sec

           = $$({10} / {300})$$ sec = $${1}/{30}$$ sec = 0.03.

Question: 5

A thief is noticed by a policeman from a distance of 200 m. The thief starts running and the policeman chases him. The thief and the policeman run at the speed of 10 km/hr and 11 km/hr respectively. What is the distance between them after 6 minutes?

(A) 90 m

(B) 100 m

(C) 110 m

(D) 120 m

Ans: B

Speed of thief = 10 km/hr

Speed of policeman = 11 km/hr

Relative speed of policeman with respect to thief = (11 – 10) km/hr
= 1 km/hr

Thief is noticed by a policeman from a distance of 200 m.

Distance covered in 6 minutes $${1000} / {60} × 6$$ = 100 m.

Distance between them after 6 minutes = 200 – 100 = 100 m.

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