Time and Distance Formulae and tips

It is important to know the relation between Time, Distance and Speed.

**1. Speed is defined as the distance covered by an object in one unit of time.**

Speed = $\text"Distance" / \text"Time"$

Distance = Speed x Time

Time = $\text"Distance" / \text"Speed"$

**2. Below formulae for converting Km/h to m/s and m/s to km/h**

⇒X km/h = ${X × 5 / 18}$ m/s

⇒X m/s = ${X × 18 / 5}$ km/h

**3. If the two objects are moving with X and Y speeds respectively, then**

Relative speed = X + Y (If the two objects are moving in opposite direction)

Relative speed = X – Y (If the two objects are moving in same direction)

4. If the ratio of speeds of X and Y is A : B, then the ratio of time taken to cover the same distance is B : A

Online Test - 1 (Time and Distance) TAKE TEST
Number of questions : 20 | Time : 30 minutes |

Online Test - 2 (Time and Distance) TAKE TEST
Number of questions : 20 | Time : 30 minutes |

Online Test - 3 (Time and Distance) TAKE TEST
Number of questions : 20 | Time : 30 minutes |

Online Test - 4 (Time and Distance) TAKE TEST
Number of questions : 20 | Time : 30 minutes |

Online Test - 5 (Time and Distance) TAKE TEST
Number of questions : 20 | Time : 30 minutes |

Online Test - 6 (Time and Distance) TAKE TEST
Number of questions : 20 | Time : 30 minutes |

**Question-1)**

**A van covers a distance of 690 km in 30h. What is the average speed of the car?**

A) 25 km/h

B) 23 km/h

C) 20 km/h

D) 18 km/h

E) None of these

Ans: B

Solution: Using the formulae, Speed = $ \text"Distance" / \text"Time"$

⇒$690 / 30$ = 23 km/h

**Question-2)**

**A certain distance is covered at a certain speed. If half of the distance is covered in double time, what is the ratio of the two speeds?**

A) 4 : 1

B) 1 : 4

C) 1 : 2

D) 2 : 1

Ans: A

Solution: Let assume certain distance = X km, X km covered in Y hr.

Then speed = $X / Y$ km/h

If the distance is covered in double time = ${(X / 2) / 2Y} = X / {4Y}$ km/h

Then required ratio is $X / Y : X / {4Y}$ = 4 : 1

**Question-3)**

**A bike runs at the speed of 50 km/h when not serviced and runs at 60 km/h when serviced. After servicing the bike covers a certain distance in 6 h. How much time will the car take to cover the same distance when not serviced?**

A) 8.2h

B) 6.5h

C) 8h

D) 7.2h

E) None of these

Ans: D

Solution: From the given data, after servicing speed of the bike = 60 km/h

Distance covered in 6h. = (60 x 6) km = 360km

When it’s not service, the time taken to cover 360 km = $360 / 50$ = 7.2h