Let the speed of train be xkm/hr
and the speed car be ykm/hr respectively.
We know that $$Speed\quad =\dfrac { Distance }{ Time } \\ \Rightarrow Time\quad =\quad \dfrac { Distance }{ Speed }$$
In Case 1
Distance travelled by train $$=$$ 160km
Distance travelled by car $$=$$ (760-160)km $$=$$ 600km
Time taken by train+Time taken by car $$=$$ 8 hours
Hence the equation becomes
$$\dfrac { 160 }{ x } +\dfrac { 600 }{ y } \quad =\quad 8$$
In case 2
Distance travelled by train $$=$$ 240km
Distance travelled by car $$=$$ (760-240)km = 520km
Time taken by train+Time taken by car $$=$$ 8 hours+12 minutes
Hence the equation becomes
$$\dfrac { 240 }{ x } +\dfrac { 520 }{ y } \quad =\quad \dfrac { 41 }{ 5 } ......(2)$$
Hence we get two equations
$$\dfrac { 160 }{ x } +\dfrac { 600 }{ y } \quad =\quad 8.........(1)\\ \quad \dfrac { 240 }{ x } +\dfrac { 520 }{ y } \quad =\quad \dfrac { 41 }{ 5 } ......(2)$$
$$Let\quad \dfrac { 1 }{ x\quad } =p\quad and\quad \dfrac { 1 }{ y } =q$$
Hence we get equations
160p + 600q $$=$$ 8........(3)
240p + 520q $$=$$ 41/5...(4)
Solving equations (3) and (4)we get p$$=$$1/80 and q $$=$$1/100
$$\quad Hence\quad p=\dfrac { 1 }{ x } \\ \Rightarrow x\quad =\dfrac { 1 }{ p } \quad =80\\ Similary\quad y\quad =\quad \dfrac { 1 }{ q } \quad =\quad 100$$
Solving we get x $$=$$ 80 and y $$=$$ 100
hence, speed of train =80km/hr and speed of car =100km/hr.