Answer:
1. 20 km/h
2. 70 m/h
3. 6.5 h
4. 4.5 s
5. 184 km
Step-by-step explanation:
For first two questions, you can use the following formula:
[tex]\displaystyle \large{s = \frac{d}{t}}[/tex]
I denote ‘s’ be speed, ‘d’ be distance and ‘t’ be time. Some books may use ‘v’ for speed instead of ‘s’ but I use ‘s’ variable instead so it makes the equation easier to memorize.
Therefore, speed = distance/time
( 1 ) The first question is given both distance be 60 km and time be 3 hours. Therefore:
[tex]\displaystyle \large{s=\frac{60}{3}}\\\displaystyle \large{s=20 \ \ \sf{km / h}}[/tex]
So for the first question, the speed is 20 km/h
( 2 ) The second is given both distance be 140 m and time be 2 hours. Therefore:
[tex]\displaystyle \large{s=\frac{140}{2}}\\\displaystyle \large{s=70 \ \ \sf{m / h}}[/tex]
Therefore, speed is 70 m/h
For the third and four questions, we will be finding time. From the speed formula:
[tex]\displaystyle \large{s=\frac{d}{t}}[/tex]
Multiply both sides by t.
[tex]\displaystyle \large{st=d}[/tex]
Divide both sides by s.
[tex]\displaystyle \large{t=\frac{d}{s}}[/tex]
Therefore, time = distance/speed
( 3 ) The question is given speed be 40 km/h and distance be 260 km. Therefore:
[tex]\displaystyle \large{t=\frac{260}{40}}\\\displaystyle \large{t=\frac{13}{2} \ \ \sf{h}}\\\displaystyle \large{t = 6\frac{1}{2} \ \ \sf{h}}\\\displaystyle \large{t= 6.5 \ \ \sf{h}}[/tex]
Therefore, time is 6.5 h
( 4 ) The question is given speed be 16 cm/s and distance be 72 cm. Therefore:
[tex]\displaystyle \large{t=\frac{72}{16}}\\\displaystyle \large{t=\frac{9}{2} \ \ \sf{s}}\\\displaystyle \large{t=4\frac{1}{2} \ \ \sf{s}}\\\displaystyle \large{t=4.5 \ \ \sf{s}}[/tex]
Therefore, time is 4.5 s
For the last question, we have to find distance. From the speed formula:
[tex]\displaystyle \large{s=\frac{d}{t}}[/tex]
Multiply both sides by t.
[tex]\displaystyle \large{st=d}\\\displaystyle \large{d=st}[/tex]
Therefore, distance = speed * time
( 5 ) The question is given time be 4 hours and speed be 46 km/h. Therefore:
[tex]\displaystyle \large{d=46 \cdot 4}\\\displaystyle \large{ d=184 \ \ \sf{km}}[/tex]
Therefore, distance is 184 km.
