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

AI Thread Summary
The discussion revolves around calculating the total mass of three parcels at a post office, where the first parcel weighs y grams, the second is 500 grams heavier, and the third is 210 grams lighter. The total mass is expressed as 3y + 290 grams. When the total mass is set to 2 kg, the equation 2000 = 3y + 290 is derived. The individual masses of the parcels are calculated to be 570 grams for the first, 1070 grams for the second, and 360 grams for the third. There is a critique regarding the clarity of the variable y and the lack of detailed work shown in the solution.
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.
 

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