Question

Some boats have motors and go further into the sea. Since they go far out they can catch more fish. These boats travel faster, at the speed of about 20 km in
one hour.
How far would the motor boats go in three and a half hours?
How much time will they take to go 85 km?

Answer 1

Answer:
  part 1 :
       Speed = 20 km / hr
         Time = 3.5 hours
         Distance  = ?
  we know that,

 speed = distance / time
 20 = distance / 3.5
or distance = 20*3.5
                 Distance = 70 km
Hence Distance traveled in 3.5 hours = 70 km
 
Part 2 :
           Speed = 20 km /hr
           Distance = 85 km
           Time  = ?
we know that ,
  speed = Distance / time
         20  = 85 /time
or time = 85/20 = 4.25 hours

Hope this helps you!!

Answer 2

data,
      speed= 20km/hr
      distance travelled in 3.5 hrs=20+20+20+10km
                                              =70km
      time taken to go 85km=
      85km=20+20+20+20+5km
             =1+1+1+1+1/4hrs
             =4hrs15min