a family travelled a total distance of 740 km in 12 hrs and 15 mins on a trip. part of the trip was by car at 80 km/hr. and the remainder by ferry at 16 km/hr. how many hrs. were spent travelling by car?

Question

anonymous · Answer

where are you so far?

cwrw238 · Answer

here are some equations arising from the problem

c + f = 740
80 = c/Tc
16 = f/Tf
Tc + Tf = 12.25

where c = distance travelled by car
          f =  ,,,,,,,,,,,,,,,,,,,,,,,,,,,,by ferry
          Tc = time by car
         Tf   =  ...........ferry

cwrw238 · Answer

aim to get  2 equations  in Tc and Tf

anonymous · Answer

Seeing the time of taking car is x hrs.

$$80x+16(12\frac{ 1 }{ 4 }-x)=740$$ $$80x+16\times12\frac{ 1 }{ 4 }-16x=740$$ $$64x+196=740$$ $$64x=740-196$$ $$64x=544$$ $$x=544\div64$$ $$x=8.5$$
The time that travelling by car was 8.5 hours.