Item A is 60% lighter than item B. Item B is 20% lighter than item C.

Item A is 60% lighter than item B. Item B is 20% lighter than item C. Item D is twice as heavy as item B. What percentage of item D is weight of item A?

Let’s write a short condition:

1) A = 0.4B (product A is 60% lighter than product B, i.e. A is only 40% of the weight of B);

2) B = 0.8C (B is 20% lighter than C or the weight of B is 80% of the weight of C);

3) D = 2C.

From (1) we express the value of the weight of the product B

B = 1 / 0.4 * B = 5/2 A

and from (2) the value of weight C through weight A

C = 1 / 0.8 B = 5/4 B = 5/4 * 5/2 A = 25/8 A.

As a result

D = 2 * 25/8 A = 25/4 A.

So, A = 4/25 D = 0.16D or 16% D.

Answer: the weight of item D is 16% of the weight of item A