Respuesta :
Answer:
B. 5 hours
Step-by-step explanation:
If the train is going 60mph and we need to find out how long it will be until it is traveling 80mph then we have to do 80-60=20 to figure out how much the speed is changeing. Since every hour the speed increases by 4mph then we have to do how much the train is increasing divided by how much it increases per hour.
20÷4=5
Therefore it will take 5 hours
Answer:
B. 5 hours
Step-by-step explanation:
80-60 = 20
So we need to find how long it takes to increase 20 mph.
at a rate of y = 4x + 60
y = 4(2) + 60 = 68 nope.
y = 4(3) + 60 = 72 nope.
y = 4(4) + 60 = 76 nope.
y = 4(5) + 60 = 80 yep.
Or you could do 20/4 = 4