Answer:
0.5 hour
Step-by-step explanation:
Given
Speed of Dina = 10 km/h
Distance = 20 km
So the time Dina taken to complete the track is:
[tex]Speed=\frac{distance}{time}\\10=\frac{20}{time}\\time=\frac{20}{10}\\ time=2\ hours[/tex]
The time taken by Dina is 2 hours. As masha started with dina but she was 4 km of the path left to cycle,
her distance covered in 2 hours was:
[tex]Distance\ covered\ by\ Masha\ in\ 2\ hours=20-4\\=16 km[/tex]
So we know the time and distance:
Now,
[tex]Speed\ of\ Masha=\frac{distance}{time}\\ =\frac{16}{2}\\ =8\ kilometer\ per\ hour[/tex]
We have to calculate the time that will be needed by MAsha to complete the track:
As we know the speed and remaining distance
[tex]Speed=\frac{distance}{time}\\8=\frac{4}{time}\\ time=\frac{4}{8}\\time=0.5\ hours[/tex]
Masha needs 0.5 hour to complete the track ..
