Question

Raj travels a part of his journey by taxi paying Rs. 15 per km and rest by train paying rs. 21 per km. If he travels total 450 km and pays rs. 8130, the distance travelled by rail is :

Answer 1

let the distance travelled by taxi be x
so the distance travelled by train=450-x

the total cost paid by him is 8130
ATQ,
15x+(450-x)21=8130
⇒15x+9450-21x=8130
⇒1320=6x
⇒x=220 km
So the distance travelled by taxi is 220 km and distance travelled by train is 230km

Answer 2

Let raj travelled by taxi and train be x,y respectively
then, 
        x+y=450   ....(1)  and  15x+21y=8130......(2)
                   subtracting 2 from 1
             15x+21y=8130*1
                x+y    =450*15
              ______________
             15x+21y=8130
             15x+15y=6750
             (-)   (-)     (-)
             ____________
                  6y=1380
                   y=1380/6
                   y=230
 substituiting y in (1)
                x+y=450
                   x=450-230
                   x=220
Therefore km travelled by car is 220 and by train is 230