120
Solving movement problems (practice)
Textbook: Part 4, lesson 120, pp. 31–33
GoalPractise movement problems: comparing speeds, departure and arrival times.
New words
comparison · taqqoslashto depart · jo‘nab ketishconstant speed · o‘zgarmas tezlikto arrive · yetib kelish
Explanation
To compare speeds, find each one with v = s : t. Speeds written in the same unit can be compared. To find the arrival time, add the travel time to the departure time. Use the inverse operation to check your answer.
Worked examples
Aziza walked 900 m in 15 minutes, Madina walked 1 km 200 m in 20 minutes. Aziza: 900 : 15 = 60 m/min, Madina: 1 200 : 20 = 60 m/min. Their speeds are equal.
A bus left at 14:00 and drove 3 hours at 45 km/h. It arrives at 17:00 and covers 45 × 3 = 135 km.
Class activity
“Train timetable”: children make a short timetable for the class, calculating departure and arrival times from the distance between towns and the speed.
Practice
1
Akmal travelled 36 km in 3 hours and Sardor 56 km in 4 hours. By how many km/h is Sardor's speed greater?
2
2
A hiker set out at 8 o'clock in the morning. He walked 24 km at 6 km/h. At what hour did he arrive? (write the hour, e.g. 12 means 12:00)
12
3
A car drove 3 hours at 60 km/h and then 2 hours at 45 km/h. How many km did it cover in total?
270
4
A bee flies at 6 m/s. How many metres does it fly in 1 minute?
360