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Comparing linear functions word problem: work

Sal is given a table of values that represents a person walking to work, and is asked to determine which verbal description represents someone starting at the same distance from work. Created by Sal Khan.

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• At , shouldn't Sal NOT check the answer? Because I calculated the slope of Charles's chart, and it turned out to be -7/5. And the problem stated that Tammy and Charles did not go to work at the same speed, so since Charles's slope is -7/5, Tammy's slope shouldn't be -7/5, so therefore, the second choice shouldn't be the answer. Am I right? I am a bit confused by this.
• One strategy to learn with word problems is read carefully and reread multiple times.
The problem states: They walked at constants speeds, but not necessarily at the same speed. The phrase "not necessarily at the same speed" does not say they don't go at the same speed. It just means, they don't have to be going at the same speed. This means the speeds could be the same or different.
Hope this helps.
• I feel there is enough information given to determine that the only right answer would be she started at 900 meters and walked 7/5 m/s, the question IS what is possible however in 50 seconds she walked 70 meters, thus she HAD to be walking more then 1 m/s if she was walking equal to or less then 7/7 m/s (say 5/7 m/s) she would have been walking less then a meter a second and not more. So walking at 5/7 m/s she would not be able to walk 70 meters per 50 seconds.
• It doesn't imply "she walked 70 meters in 50 seconds", only Charles.
• ok i have a ligintiment question in the maths this
Mr. Mole and Bugs Bunny started digging their way into the ground from different locations at the same time. They each dug at a constant rate.
The following equation gives Mr. Mole's altitude (in meters relative to the ground) as a function of time (in minutes).
A=−4−0.6t
Bugs Bunny's altitude (in meters relative to the ground) as a function of time (in minutes) is given by the following table of values:
time (min) / altitude(meters)
2 / -1.6
9 / -7.2
16 / -12.8
Who dug faster?
A
Mr. Mole
B
Bugs Bunny
C
They both dug at the same rate

Who started at a higher altitude?
options the same
edit: what if one started on a hill and the other in the valley (this was my immediate thought) *why drag in bugs bunny *
• Would you always apply the same idea?
• Sometimes, I wonder if it's possible to use proportions instead of equations, graphs, or tables when solving relationship problems. Proportions seem like they could be a simpler and quicker method.
• Proportions only work when you can set up the equation as one fraction = another. Or, you have an equation like y=kx where "k" is the constant of proportionality. Anything different from those would not be a proportional relationshsip.
• If Charles is walking at 7/5 m/s and their speeds 'aren't necessarily the same' then how could Tammy be walking at 7/5 m/s too?
• It is not saying that they are walking at different speeds,it is only saying that they might be.
• This was made 5yrs ago trippin¯\(ツ)
• sal is giving wrong answer in word problem(work) out of two 1 is right other is wrong.
(1 vote)
• Sal is right in both cases, the question states to select any that apply which means there could be more than one answer. In the U.S., this is done on tests by giving a Roman Numeral to each answer, then the choices would be like A) I and II only, B) II and III only, C) I, II, and III only, etc.