Odpowiedzi

2010-04-14T19:08:28+02:00
T1= 25min = 5/12h
t2= 20 min = 1/3h
v1= x km/h
v2= (x +3)km/h
s = y km

s = t x v; [s]= h x km/h = km - h skracamy

t1 x v1 = s
t2 x v2 = s

5/12 x X = y
1/3(x + 3) = y

5/12x=y
1/3x + 1/3 x 3 = y - 3 skracamy

5/12x=y
1/3x + 1 = 5/12x

5/12x=y
5/12x = 1/3x + 1 - zamieniamy stronami

5/12x=y
5/12x - 1/3x = 1

5/12x=y
5/12x - 4/12x = 1

5/12x=y
1/12x = 1 /12

5/12x=y
x=12

5/12 x 12 = y
x=12

y= 5km - 12 skracamy
x=12km/h

v1 = 12km/h
v2 = 15 km/h
3 1 3