Question

The average weight of 3 containers A,B and C is 3.2kg. Container A is twice as heavy as container B. Containers B is 400 g heavier than container C. Find the weight of container C.

Answer 1

The weight of container C is 2.1kg.

Explanation:

This question is solved using a system of equations.

I am going to say that:

x is the weight of container A.

y is the weight of container B.

z is the weight of container C.

The average weight of 3 containers A,B and C is 3.2kg.

This means that the total weight is 3*3.2 = 9.6kg. So

`x + y + z = 9.6`

Container A is twice as heavy as container B.

This means that
`x = 2y`.

Containers B is 400 g heavier than container C.

400g is 0.4kg. So

This means that
`y = z + 0.4`, or
`z = y - 0.4`

Replacing y and z as functions of x in the first equation:

`x + y + z = 9.6`

`2y + y + y - 0.4 = 9.6`

`4y = 10`

`y = (10)/(4) = 2.5`

Container C

`z = y - 0.4 = 2.5 - 0.4 = 2.1`

The weight of container C is 2.1kg.