Given :
Apa-bear weighs 250 lb.
Mama-bear weighs 50 pounds less than Papa-bear does.
Their 2 cubs weigh 80 pounds each.
To Find :
The total weight of the Bear family .
Solution :
Weight of mama bear = .
Total weight is the sum of all all weight .
Therefore , total weight of the Bear family is 610 lb .
Hence , this is the required solution .
Elimination Method
If we multiply the equation 3 by (-1) we obtain this:
If we add them we obtain 0, therefore there are infinite solutions. So, let's write it in terms of Z
1. Using the 3rd equation we can obtain X(Y,Z)
2. We can replace this value of X in the 1st and 2nd equations
3. If we simplify:
4. We can obtain Y from this two equations:
5. Now, we need to obtain X(Z). We can replace Y in X(Y,Z)
6. If we simplify, we obtain:
7. In conclusion, we obtain that
(X,Y,Z) =