Can you calculate the total mass of three parcels at a post office?

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Discussion Overview

The discussion revolves around calculating the total mass of three parcels at a post office, expressed in terms of a variable representing the mass of the first parcel. Participants explore the formulation of the total mass and critique the presentation of the solution.

Discussion Character

  • Homework-related
  • Mathematical reasoning
  • Debate/contested

Main Points Raised

  • One participant presents the total mass of the three parcels as 3y + 290 grams, based on the mass of the first parcel being y grams.
  • Another participant agrees with the calculation but emphasizes the need to clarify what "y" represents in the context of the problem.
  • A critique is raised regarding the lack of shown work in arriving at the individual masses of the parcels, suggesting that the solution should include more detailed steps.
  • Some participants express a light-hearted acknowledgment of the critique, with one noting their age and implying a distance from being a student.

Areas of Agreement / Disagreement

Participants generally agree on the formulation of the total mass but express disagreement regarding the clarity of the variable "y" and the presentation of the solution steps. The discussion remains unresolved on how to best present the solution.

Contextual Notes

There is an assumption that "y" represents the mass of the first parcel, but this is not explicitly stated in the initial solution. The critique highlights the importance of showing work in mathematical problems.

Johnx1
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At a post office, there are three parcels of different masses. The mass of the first parcel is y grams. The mass of the second parcel is 500 grams greater than that of the first parcel. The third parcel is 210 grams lighter than the first parcel.

a) Find the total mass, in grams, of the three parcels in terms of y.

My answer: y + (y + 500) + (y - 210) = 3y + 290b) the total mass of the three parcels is 2kg. find the mass of each parcel in grams.

my answer: 2000 = 3y + 290.

1st = 570
2nd = 1070
3rd = 360
 
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Johnx said:
At a post office, there are three parcels of different masses. The mass of the first parcel is y grams. The mass of the second parcel is 500 grams greater than that of the first parcel. The third parcel is 210 grams lighter than the first parcel.

a) Find the total mass, in grams, of the three parcels in terms of y.

My answer: y + (y + 500) + (y - 210) = 3y + 290b) the total mass of the three parcels is 2kg. find the mass of each parcel in grams.

my answer: 2000 = 3y + 290.

1st = 570
2nd = 1070
3rd = 360

Looks good! (Yes)
 
my answer: 2000 = 3y + 290.

My criticism would be that you have an equation in "y" without saying what "y" represents! You are taking y to be the weight, in grams, of the first package but you should say that. Further you jump immediately to the answer
1st = 570
2nd = 1070
3rd = 360
without showing any work. Can we assume that you showed your work on the paper you turned in?
 
Country Boy said:
without showing any work. Can we assume that you showed your work on the paper you turned in?
Im actually too old to be a school student :-)
 
Country Boy said:
My criticism would be that you have an equation in "y" without saying what "y" represents! You are taking y to be the weight, in grams, of the first package but you should say that.

The problem states:

Johnx said:
The mass of the first parcel is y grams.
 
I completely missed that! But I did get a chance to be a curmudgeon.