If such a car travels 220 miles in 4 hours, how long does it take to travel

J

JadeMiller

New member
385 miles? For a car moving at a constant speed, the distance traveled varies directly with the time spent driving. If such a car travels 220 miles in 4 hours, how long does it take to travel 385 miles?
 
J

jUiCe

Member
Figuring out from the already given statistics, it travels 220 miles in four hours, that means it's going at a rate of 55 miles per hour. 385 miles/ 55 = 7 hours.
 
D

DopeyDinosaur

New member
4 hours = 220 miles

How many hours does it take to go one mile? = 4 / 220

Now multiply that by 385 to get how many hours it takes to go that far.

Then use the decimal portion of the answer and multiply it by 60 to get minutes.

Then use the decimal portion OF THAT and times it by 60 to get seconds (if any).
 
A

Aaron

Member
Use this formula to find that:
Rate of travel (R) * Time of travel(T) = Distance traveled(D)

We don't get the rate of travel, but we get the time and distance. That allows us to find the rate w/ this equation.

R*4 = 220
R = 55

now, we plug that value and the new distance to get our new time.
55*T = 385
T = 7

It takes 7 hours to travel 385 miles at a constant speed of 55mph.

Hope that helps!
 
B

brian

Active member
Since the distance traveled varies directly as the time spent driving, we have that:
D = kt, where D is the distance, k is a constant, t is the time spent driving.

Since D = 220 when t = 4:
220 = 4k ==> k = 55.

So, the equation that relates D and t is:
D = 55t.

When D = 385:
385 = 55t ==> t = 7 hours.

I hope this helps!
 
R

Rob

Member
Since speed is constant. you can find speed using the first two givens (220miles and 4 hours)
distance: 220 miles
time: 4hours
speed = distance/time
= 220/4
= 55miles/hr
and if you traveled 385 miles
distance: 385 miles
speed = 55miles/hr
time = distance/speed
= 385/55
= 7hrs
Answer: 7 hours!
 
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