SOLUTION: 1. Two cars leave town at the same time in opposite directions. One travels 35 km/h and the other 40 km/h. In how many hours will they be 200 km apart?
2. Two cars leave town at t
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Question 1014408: 1. Two cars leave town at the same time in opposite directions. One travels 35 km/h and the other 40 km/h. In how many hours will they be 200 km apart?
2. Two cars leave town at the same time in the same direction. One travels 35 mi/h and the other 40 mi/h. In how many hours will they be 15 miles apart?
I can't figure these problems out. It would help out if somebody could help me understand them. My email is alecblake009@hotmail.com
Found 2 solutions by stanbon, josmiceli:
Answer by stanbon(75887) (Show Source): You can put this solution on YOUR website!
1. Two cars leave town at the same time in opposite directions. One travels 35 km/h and the other 40 km/h. In how many hours will they be 200 km apart?
The cars are separating at a rate of 35+40 = 75 km/h
Equation:
time = distance/rate
Ans: time = 200km/75km/h = (200/75)hr = 2 2/3 hrs = 2hr 40min
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2. Two cars leave town at the same time in the same direction. One travels 35 mi/h and the other 40 mi/h. In how many hours will they be 15 miles apart?
------
slower car DATA: distance = 35t, where t is the number of hours
faster car DATA: distance = 40t,
------
Equation:
faster dist - slower dist = 15
40t - 35t = 15mi
5t = 15 mi
time = 3 hrs
----------------
Cheers,
Stan H.
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Answer by josmiceli(19441) (Show Source): You can put this solution on YOUR website!
All you need is [ distance ] = [ rate ] x [ time ]
Each of the cars needs it's own equation.
Let = distance traveled by the slower car
until they are km apart
= distance traveled by faster car
until they are km apart
Let = time in hrs when they are km apart
--------------------------
Equation for slower car:
(1)
Equation for faster car:
(2)
--------------------
Substitute (1) into (2)
(2)
(2)
(2) hrs
(2) hrs
min
They will be 200 km apart in 2 hrs and 40 min
--------------------------
check:
(1)
(1)
(1)
and
(2)
(2)
(2)
(2)
OK
----------------------------
----------------------------
Be careful in the 2nd problem because the cars get
further apart as time goes on, but not as much as
when they were going in opposite directions
--------------
Let = distance in miles traveled by slower car
until they are miles apart
= distance in miles traveled by faster car
until they are miles apart
Let = time in hrs until they are miles apart
--------------------
Equation for slower car:
(1)
Equation for faster car:
(2)
--------------------
Substitute (1) into (2)
(2)
(2)
(2) hrs
In 3 hrs they will be 15 mi apart
---------------------------
check:
(1)
(1)
(1)
and
(2)
(2)
(2)
(2)
OK
Hope this helps
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