<PRE><B>Question 1101074</B>
If the weight of parcel A is represented by a, the weight of parcel B is represented by b and the weight of parcel C is represented by c a.
 Derive a system of three equations in a, b and c. b.
 Using the inverse method derive the combined weight of parcel A, B and C.  
:
If parcel A and B together weigh 24 kgs,
a + b = 24
 but parcel B and C together weighs only 21 kgs.
b + c = 21
 When parcel A and C are paired, the combined weight is 27kgs.
a + c = 27
:
write the system like this
a + b + 0 = 24
0 + b + c = 21
a + 0 + c = 27
------------------Add
2a + 2b + 2c = 72
simplify divide by 2
a + b + c = 36 kg is the combined weight of the 3 parcels
:
:
Not sure if this is the inverse method, but this sure is the simplest. 
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