Question

A car made a run of 390 km in x hours,If the speed had been 4km/hr more , it would have taken 2 hours less for the journey.
Find x.
@welshfella
@sepeario

Answer 1

@Sepeario

Answer 2

\[x - 2 = \frac{ 390 }{ 4 }\]
\[x = 2 + \frac{ 390 }{ 4 } = 99.5\]

Answer 3

It is a hell of a long trip :D

Answer 4

Whta?

Answer 5

The ans is 15
But how?

Answer 6

ok so you do: (390/x)+4 because the car made the run of 390 km in x hours and you want to know what would happen if you increased the speed 4 km.
do you get the first part?

Answer 7

no

Answer 8

velocity v = distance / time
= 390/x

v increases by 4 and x is reduced by 2, therefore

v + 4 = 390 / (x -2)
v = [390 / (x -2] - 4

eliminating v

390/x = [390/x-2) - 4]

Answer 9

Can't I
390/x - 390/x+4 = 2
Do this?

Answer 10

sorry i got that wrong

Answer 11

390/x - 390/x+2 = 4

Answer 12

no that not correct

Answer 13

its