Question

A scootorist covers every one third of the total
distance at 10 km/hour, 20 km/hour and
60 km/hour respectively, His average speed is -
(1) 30 km/h
(2) 90 km/h
(3) 36 km/h
(4) 18 km/h​

Answer 1

Answer:

Let the total distance travelled be x km Then total time taken =  

10

x/3

​  

+  

20

x/3

​  

+  

60

x/3

​  

=  

30

x

​  

+  

60

x

​  

+  

180

x

​  

 

=  

180

6x+3x+x

​  

=  

180

10x

​  

=  

18

x

​  

 hrs Then average speed = =  

Totaltimetaken

Totaldistancetravelled

​  

 

=  

x/18

x

​  

 km/hr = 18 km/hr

Explanation:

Answer 2

Answer:hen average speed =

2×30×70/30+70

​

=42km/hr

So required distance traveled in 10 hours =42×10=420 km

Explanation: