Can you solve this math problem?

5,970 Views | 48 Replies | Last: 2 yr ago by RobertHughes
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Imagine a car sitting at the bottom of a hill.

The hill is 1 mile to the top, and then 1 mile down to the bottom of the other side.

The car makes it to the top, but the car doesn't have a great engine so it only averages 15 mph on the way up.

How fast does the car have to travel going down the hill to complete the entire 2 mile journey with an average speed of 30 mph?
B-1 83
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The treadmill is moot.
Being in TexAgs jail changes a man……..no, not really
concac
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The answer is C.
StinkyPinky
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Fast enough
Doctor Rosenrosen
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Captain Positivity said:

Imagine a car sitting at the bottom of a hill.

The hill is 1 mile to the top, and then 1 mile down to the bottom of the other side.

The car makes it to the top, but the car doesn't have a great engine so it only averages 15 mph on the way up.

How fast does the car have to travel going down the hill to complete the entire 2 mile journey with an average speed of 30 mph?
It can't. It already wasted all it's time on the first half of the trip.
Anchorhold
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How long is left on the lease?
wbt5845
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Warp 1
Doctor Rosenrosen
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Doctor Rosenrosen said:

Captain Positivity said:

Imagine a car sitting at the bottom of a hill.

The hill is 1 mile to the top, and then 1 mile down to the bottom of the other side.

The car makes it to the top, but the car doesn't have a great engine so it only averages 15 mph on the way up.

How fast does the car have to travel going down the hill to complete the entire 2 mile journey with an average speed of 30 mph?
It can't. It already wasted all it's time on the first half of the trip.
Furthermore, if the down trek was 1.0000001 miles instead of 1 then it would be possible to average 30 mph.
Doctor Rosenrosen
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dp
Dad-O-Lot
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not possible
THE_CHOSEN_ONE
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Speed of light
ThunderCougarFalconBird
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$potato. Duh.
The Porkchop Express
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The doctor is his mother.
Ginormus Ag
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I was told there would be no math.
Username checks out.
whoop1995
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Sorry not a math major but wouldn't the second mile have to be made at 45 mph?

(X +15)/2=30

X+15=60

X=45
Ag81Golf
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What does the car's tits look like?
TriAg2010
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whoop1995 said:

Sorry not a math major but wouldn't the second mile have to be made at 45 mph?

(X +15)/2=30

X+15=60

X=45


Negative - look at the minutes traveled. Averaging 30 mph means traveling one mile every two minutes. At 15 mph, it takes four minutes to reach the peak. You would need to travel instantaneously fast the last mile to average two minutes per mile.
whoop1995
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TriAg2010 said:

whoop1995 said:

Sorry not a math major but wouldn't the second mile have to be made at 45 mph?

(X +15)/2=30

X+15=60

X=45


Negative - look at the minutes traveled. Averaging 30 mph means traveling one mile every two minutes. At 15 mph, it takes four minutes to reach the peak. You would need to travel instantaneously fast the last mile to average two minutes per mile.
Christ - 7 years of college, down the drain

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Eliminatus
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whoop1995 said:

Sorry not a math major but wouldn't the second mile have to be made at 45 mph?

(X +15)/2=30

X+15=60

X=45
This is one of those low brow misleading word problems.

The key twist is here:
Quote:

complete the entire 2 mile journey

Must complete means a set boundary condition making it impossible to do since the condition was already met before any further calculations can take place.

"Got you good, you dumb piece of *****"
- whoever comes up with these things
aggie_wes
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Who said you only had an hour to complete the trip?
whoop1995
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Eliminatus said:

whoop1995 said:

Sorry not a math major but wouldn't the second mile have to be made at 45 mph?

(X +15)/2=30

X+15=60

X=45
This is one of those low brow misleading word problems.

The key twist is here:
Quote:

complete the entire 2 mile journey

Must complete means a set boundary condition making it impossible to do since the condition was already met before any further calculations can take place.

"Got you good, you dumb piece of *****"
- whoever comes up with these things
Thanks to all of you for the explanation - jacked that one up big time
Eliminatus
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aggie_wes said:

Who said you only had an hour to complete the trip?
The problem statement. The units matter. They use mph which is a function of time and length. The key statement I pointed out above sets a condition of 2 miles completed. Meaning for mph to stay true, the time is now also set.

So with the time being set, you have to calculate for that time.

Variables: 2 miles is known, time is not, must equal 30mph.

Some basic algebra and it is found that the car must travel one mile every 2 minutes to average 30mph.

However the first part of the equation of reaching the top at 15 mph means 4 minutes have already been used. You can't have that and have the second part of the question also be true invalidating the whole thing.
Condition of 30mph avg. was already passed half way up the front side.

For the record, I hate these.
Eliminatus
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whoop1995 said:



Thanks to all of you for the explanation - jacked that one up big time
Eh, these are just word traps designed to trick people. I only know this one because I ran across something similar years ago.
Anchorhold
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GB idiots have reading comprehension problems? GASP So that's why so many people can't follow rule one.
AgsMyDude
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Does the driver has big cans?
toucan82
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What if you used negative time?
213 Grove
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Sticks&Stones
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Captain Positivity said:

Imagine a car sitting at the bottom of a hill.

The hill is 30 miles to the top, and then 30 miles down to the bottom of the other side.

The car makes it to the top, but the car doesn't have a great engine so it only averages 30 mph on the way up.

How fast does the car have to travel going down the hill to complete the entire 60 mile journey with an average speed of 60 mph?


Change the variables to something easy to work in your head.

To average 60 mph over a 60 mile trip, you have to complete the trip in exactly one hour. You already used exactly one hour traveling the first 30 miles at 30 mph.

It can't be done
azul_rain
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im a business major **********, i put logos on power points and deal with the ******* people
lb3
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Where is physics clown when we need him?

Damn you PhotoBucket!
ABATTBQ11
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15 mph since it takes the tunnel through the hill and is a piece of ****
ABATTBQ11
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Seems appropriate

Not a Bot
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The solution:
Ghost91
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Depends. What was in the kitchen?
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