Question

preciso pra amanha cedo

Answer 1

12-

S1 = 70 . 4 = 280km
S2 = 50 . 4 = 200km

t1 = 4h
t2 = 4h

Vm = ( S1+S2 ) / ( t1+t2 )
Vm = 480 / 8
Vm = 60km/h

13-

S1 = x
S2 = x

t1 = x/90
t2 = x/60

Vm = ( S1+S2 ) / ( t1+t2 )
Vm = 2x / ( x/90 + x/60 )
Vm = 2x / 5x/180
Vm = 2x / x/36
Vm = ( 2x . 36 ) / x
Vm = 2.36
Vm = 72km/h

14-

S1 = x
S2 = x

t1 = x/40
t2 = x/60

Vm = ( S1+S2 ) / ( t1+t2 )
Vm = 2x / ( x/40 + x/60 )
Vm = 2x / 5x/120
Vm = 2x / x/24
Vm = 2/ 1/24
Vm = 2.24
Vm = 48km/h