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

Johnx1
Messages
48
Reaction score
0
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
 
Mathematics news on Phys.org
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.
 

Thread 'What Exactly is Dirac’s Delta Function? - Insight'

Insights auto threads is broken atm, so I'm manually creating these for new Insight articles. In Dirac’s Principles of Quantum Mechanics published in 1930 he introduced a “convenient notation” he referred to as a “delta function” which he treated as a continuum analog to the discrete Kronecker delta. The Kronecker delta is simply the indexed components of the identity operator in matrix algebra Source: https://www.physicsforums.com/insights/what-exactly-is-diracs-delta-function/ by...
View full post »

Thread 'Fermat's Last Theorem'

Fermat's Last Theorem has long been one of the most famous mathematical problems, and is now one of the most famous theorems. It simply states that the equation $$ a^n+b^n=c^n $$ has no solutions with positive integers if ##n>2.## It was named after Pierre de Fermat (1607-1665). The problem itself stems from the book Arithmetica by Diophantus of Alexandria. It gained popularity because Fermat noted in his copy "Cubum autem in duos cubos, aut quadratoquadratum in duos quadratoquadratos, et...
View full post »

Thread 'Useless continued fraction for 1'

I'm interested to know whether the equation $$1 = 2 - \frac{1}{2 - \frac{1}{2 - \cdots}}$$ is true or not. It can be shown easily that if the continued fraction converges, it cannot converge to anything else than 1. It seems that if the continued fraction converges, the convergence is very slow. The apparent slowness of the convergence makes it difficult to estimate the presence of true convergence numerically. At the moment I don't know whether this converges or not.
View full post »

Hot Threads

Recent Insights

Back
Top