**Question 1:**The distance from town

*A*to town

*B*is 120 km. A car leaves town

*A*for town

*B*at 11.00 a.m. The average speed is 80 km h

^{-1}.

At what time does the car arrive at town

*B*.

*Solution*:$\begin{array}{l}\text{Timetaken}=\frac{\text{distancetravelled}}{\text{averagespeed}}\\ =\frac{120\text{km}}{80{\text{kmh}}^{-1}}\\ =\frac{3}{2}\text{hours}\\ \text{=1hour30minutes}\\ \text{1hour30minutesafter11}\text{.00a}\text{.m}\text{.is12}\text{.30p}\text{.m}\text{.}\end{array}$

**Question 2:**Kenny drives his car from town

*P*to town

*Q*at a distance of 180 km in 3 hours.

Faisal takes 30 minutes less than Kenny for the same journey.

Calculate the average speed, in km/h, of Faisal’s car.

*Solution*:$\begin{array}{l}\text{TimetakenbyFaisal}\\ \text{=3hours}-30\text{minutes}\\ \text{=3hours}-\frac{1}{2}\text{hour}\\ \text{=2}\frac{1}{2}\text{hours}\\ \\ \text{AveragespeedofFaisal'scar}\\ =\frac{\text{distancetravelled}}{\text{timetaken}}\\ =\frac{180\text{km}}{\text{2}\frac{1}{2}\text{hours}}\\ =72\text{km/h}\end{array}$

**Question 3:**Rafidah drives her car from town

*L*to town

*M*at an average speed of 90 km/h for 2 hours 40 minutes. She continues her journey for a distance of 100 km from town

*M*to town

*N*and takes 1 hour 20 minutes.

Calculate the average speed, in km/h, for the journey from

*L*to

*M.*

*Solution*:$\begin{array}{l}\text{Distance}=\text{averagespeed}\times \text{timetaken}\\ \text{Distancefrom}L\text{to}M=90\times 2\frac{40}{60}\\ \text{}=90\times 2\frac{2}{3}\\ \text{}=90\times \frac{8}{3}\\ \text{}=240\text{km}\\ \\ \text{Totaldistancefrom}L\text{to}N=240+100\\ \text{}=340\text{km}\\ \\ \text{Totaltimetaken=2hours40minutes+1hour20minutes}\\ \text{=4hours}\\ \text{Averagespeedforthejourneyfrom}L\text{to}N=\frac{340\text{km}}{4\text{h}}\\ \text{}=85\text{km/h}\end{array}$

**Question 4:**Susan drives at an average speed of 105 km/h from town

*F*to town

*G*.

The journey takes 3 hours.

Susan takes 30 minutes longer for her return journey from town

*G*to town

*F*. Calculate the average speed, in km/h, for the return journey.

*Solution*:$\begin{array}{l}\text{Distancefrom}F\text{to}G\\ \text{=105km/h}\times \text{3hours}\\ \text{=315km}\\ \\ \text{Averagespeedforreturnjourney}\\ =\frac{\text{distancetravelled}}{\text{timetaken}}\\ =\frac{315\text{km}}{3\frac{1}{2}\text{hours}}\\ =90\text{km/h}\end{array}$

**Question 5:**Table below shows the distances travelled and the average speeds for four vehicles.

Vehicle | Distance (km) | Average speed (km/h) |

A | 230 | 115 |

B | 250 | 100 |

C | 170 | 85 |

D | 245 | 70 |

*Solution*:$\begin{array}{l}\text{Timetakenforvehicle}A=\frac{230}{115}=2\text{hours}\\ \text{Timetakenforvehicle}B=\frac{250}{100}=2\frac{1}{2}\text{hours}\\ \text{Timetakenforvehicle}C=\frac{170}{85}=2\text{hours}\\ \text{Timetakenforvehicle}D=\frac{245}{60}=3\frac{1}{2}\text{hours}\end{array}$

Thus, the vehicles A and C took the same time to complete the journey.