Author Manisha Gupta asked on 2019-07-22 13:26:00

Method I

Distance =speed * time 

let distance by each will be x

total distance =3x

Distance /Speed =Time

x/10+x/30+x/8=15.5/60

x(62/240)=15.5/60

x=(15.5*240)/(60*62) =1

Total Distance=3x=3*1=3

Method II

let will be 240 ( LCM of 10,30,8)

t1=80/10=8

t2=80/30=8/3

t3=80/8=10

total time =24+8+30=62/3

Unitry method

62hr/3 =240KM

1hr =240*3/62

15.5/60hr =(240*3/62)*15.5/60 = 3