two cars leave at the same time from opposite points on a road. One travels at 40km/h and the other at 60km/h. If the distance between the starting points is 300 km, how many hours will it take to meet?
Respuestas
Respuesta:
NOSE ABLAR INGLES
Explicación paso a paso:
PERDON PLISS
Respuesta:
2 hours and 39 minutes approximately
Explicación paso a paso:
we make a graphical representation of the mobiles A and B
∙ A⟶ ————————— ⟵ ∙ B
∙ A⟶ – x ——— (200000-x) —- ⟵ ∙ B
Va = 30 km / h = 30. (1000) / 3600 = 8.33 m / s
then the distance traveled from A will be:
Vb = 12.5 m / s
Va = x / ta
ta = x / Va
Vb = (200000 -x) / tb
tb = (200000-x) / Vb
But since the mobiles came out simultaneously, then the time from a to the same time from b.
ta = tb
x / Va = (200000-x) / Vb
x / 8.33 = (200000 -x) /12.5
12.5x = 8.33 (200000 -x)
12.5x + 8.33x = 1666000
20.83x = 1666000
x = 1666000 / 20.83
x = 79,980.79 meters = 79.98 Km
Then the distance traveled from A will be:
X = 79.98 Km
And the distance traveled from B will be:
200 -79.98 = 120.02 Km
The time to meet will be:
ta = tb = t
t = 79.98 km / 30 km / h = 2.66 hours = 2 hours and 39 minutes approximately