## Time, Speed And Distance

**Time Speed & Distance Formula **

**b) When Distance is constant**

**Time∝1/speed**

When Time is constant

**Distance ∝ speed **

**
** When speed in constant

**Distance ∝ Time**

**
** c) Average speed = (Total Distance )/(Total Time Taken)

**When Distance is equal**

**Average speed**

**= 2xy/(x + y)**

**x, y → speeds**

**Time Speed & Distance: Questions **

**Q1. A car takes half of the time taken by truck to go from Lucknow to Bombay. A truck takes 20 hours to go for the same journey. What is the speed of truck, if the speed of car be 120 km/hr.**

**Q2. Shweta when increases her speed from 24 km/hr to 30 km/hr she takes one hour less than the usual time to cover a certain distance. What is the distance usually covered by Shweta?**

**Q3. Kriplani goes to school at 20 km/hr and reaches the school 4 minutes late. Next time, she goes at 25 km/hr and reaches the school 2 minutes earlier than the scheduled time. What is the distance of her school?**

**Q4. Udai travels half of his journey by train at the speed of 120 km/hr and rest half by car at 80 km/hr. What is the average speed?**

**Q5. Walking at 4/5 of his normal speed, Dewang is 15 minutes late in reaching his club. What is the usual time taken by him to cover the distance?**

**Relative Speed Formula & Questions**

(a) When two bodies move in the same direction, Let the speed of two bodies be S_A & S_B.

**Relative speed = S_A – S_B**

**
** (b) When two bodies are moving in the opposite direction. Let the speed of two bodies be S_A & S_B.

**Relative speed = S_A + S_B.**

**
** (c) When two bodies moving towards each other than time taken by them to meet.

**D→ Distance between two bodies.**

**S_A, S_B→ Speed of two bodies.**

**T, time taken to meet each other = D/(S_A+ S_B )**

**
** (d) When two bodies are moving in opposite direction, time taken to meet.

**D→ Distance between the two bodies.**

**S_A, S_B→ Speed of two bodies**

**T, time taken = D/(S_A – S_B )**

**
** (e) If two persons A & B, start at the same time from P and Q towards each other and after crossing they take T₁ & T₂ hrs in reaching Q & P

**S_A/S_B =√(T_B/T_A )**

**Q1. The distance between 2 places R and S is 42 km. Anita starts from R with a uniform speed of 4 km/hr towards S and at the same time Romita starts from S towards R also with some uniform speed. They meet each other after 6 hours. The speed of Romita is**

**Q2. The distance between two cities A and B is 330 km. A train starts from A at 8 a.m. and travels towards B at 60 km/hr. Another train starts from B at 9 a.m. and travels towards A at 75 km/hr. At what time do they meet?**

**Q3. A thief Bhagu Ram is spotted by the policeman Pakad Singh from a distance of 200m. Once they see each other they start Running. What is the distance Bhagu Ram, who is running at 5 km/hr would have covered before being caught by Pakad Singh running at 7 km/hr?**

**Q4. A train starts from A to B at 9:00 am and takes 6 hours to travel to B. Another train starts from B to A at 10:00 am and takes 8 hours to travel to A. At what time both train will meet?**

**Q5. Abhinav leaves Mumbai at 6 am and reaches Bangalore at 10 am Praveen leaves Bangalore at 8 am and reaches Mumbai at 11:30 am. At what time do they cross each other?**