Respuesta :
Answer:
[tex]t=54.8571428571km[/tex]
Step-by-step explanation:
[tex]4(t+3)+10(t+3)----> 4t+12+10t+30\\\\810km= 14t+42\\768km=14t\\t= 54.8571428571km[/tex]
Hope This Helps!!!!
Answer:
45 km/h
Step-by-step explanation:
4(t+3) = 4t + 12
10(t+3) = 10t + 30
(4t + 12) (10t + 30) = 40t² + 240t + 360 = 810
4t² + 24t - 45 = 0
(2t - 3) (2t +15) = 0
t = 3/2 or t = - 15/2
Speed: 10(t+3) = 45 or -75
speed is positive: speed = 45 km/h
