Question

Dina and Masha start cycling on a 20 km bike path at the same time. When Dina reaches the end of the path, Masha still has 4 km of the path left to cycle. If Dina's cycling speed is 10 km/h, how much time longer will Masha need to complete the path?

Answer 1

Answer:

30 minutes

Step-by-step explanation:

Answer 2

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:

$Speed=\frac{distance}{time}\\10=\frac{20}{time}\\time=\frac{20}{10}\\ time=2\ hours$

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:

$Distance\ covered\ by\ Masha\ in\ 2\ hours=20-4\\=16 km$

So we know the time and distance:

Now,

$Speed\ of\ Masha=\frac{distance}{time}\\ =\frac{16}{2}\\ =8\ kilometer\ per\ hour$

We have to calculate the time that will be needed by MAsha to complete the track:

As we know the speed and remaining distance

$Speed=\frac{distance}{time}\\8=\frac{4}{time}\\ time=\frac{4}{8}\\time=0.5\ hours$

Masha needs 0.5 hour to complete the track ..