Question 301905

If it reaches on time let the number of hours be x
Distance = rate * time


(x+3)*60=(x-1)*90

60x+180=90x-90

-30x=-270

x=-270/-30

x= 9 hours

take any one of the speeds

60 kmph it takes 3 hours more so it travels 12 hours 

12 *60 = 720 km

90kmh it takes 1 hour less so itakes 8 hours

8*90 =720 kms

cheers 

Ananth