average weight of 3 containers a b and c is 3.2 kg. container a is 2x as heavy as container b. Container b is 400g heavier than container c. find weight of container c. thanks,

Question

anonymous · Answer

a + b +c 
-------- = 3.2 kg    ---> 1st equation
      3
a = 2b                      ---> 2nd equation
b = c + 0.4kg           ---> 3rd equation                    0.4 kg = 400g
b - 0.4kg = c

a + b + c
--------- = 3.2kg           a = 2b, c = b - 0.4kg
      3
2b + b +b - 0.4kg
---------------- = 3.2kg
              3
4b - 0.4kg = 9.6kg
4b = 10kg
       10kg
b = -----
          4
b = 2.5kg
a = 5kg
c = 2.1kg

anonymous · Answer

kelu_baog had answered it correctly but isn't that 'weight' is also important because $$mass \neq weight$$