Question

Question 19

Distance between Bholu’s and Golu’s house is 9 km. Bholu has to attend Golu’s birthday party at 7 o’clock. He started from his home at 6 o’clock on his bicycle and covered a distance of 6 km in 40 minutes. At that point he met Chintu and he spoke to him for 5 minutes and reached Golu’s birthday party at 7 o’clock. With what speed did he cover the second part of the journey? Calculate his average speed for the entire journey.

Answer 1

$40minutes=\frac{40}{60}=\frac{2}{3}hrs$
$Speed=\frac{distance}{time}=\frac{6}{\frac{2}{3}}=3\times 3=9$ km/hr for the first 6 km.
Now distance travelled = 3 km
Time taken = 15 minutes = $\frac{15}{60}=\frac{1}{4}$ hrs.
$Speed=\frac{distance}{time}=\frac{3}{\frac{1}{4}}=3\times 4=12$ km/hr for rest of the journey.
Avg. speed = $\frac{9}{1}=9km/hr$