a vehicle travels at a certain average speed for a distance of 63km and then travels a distance of 72km at an average speed of 6km/h more than its original speed. if it takes 3 hours to complete the total journey, what si its original average speed?

Question

anonymous · Answer

63/v + 72/(v+6) = 3

parthkohli · Answer

The vehicle travels those 63 kilometers, let's say, at $x$ kilometers per hour.  Then the next 72 kilometers would be at a speed of $x + 6$.

How would you express the time taken to travel those $63$ kilometers in terms of $x$?

parthkohli · Answer

And how would you express the time taken to travel the next $72$ kilometers?

anonymous · Answer

63/x - 72/x+ 64 = 3 ...... wt after ths?

anonymous · Answer

???

ranga · Answer

63/v + 72/(v+6) = 3
multiply each term by v(v+6)
63(v+6) + 72(v) = 3v(v+6)

If you simplify you will get a quadratic equation in v.  And then you can solve for v.

anonymous · Answer

i got, ... -3x^2 + 52x + 378 = 0 , ... now how to slove ths by completing the square method ?

anonymous · Answer

any1 thr???