Alloy copper:tin = 3:2. After adding 250 g copper, copper becomes twice tin:\nFind tin (g) in the original alloy.

Introduction / Context:
This is a ratio adjustment problem: adding a metal shifts the copper:tin relation to a specified post-addition ratio.

Given Data / Assumptions:

• Initial copper:tin = 3:2 ⇒ let copper = 3k, tin = 2k (g).
• Add 250 g copper; then copper becomes twice tin.

Concept / Approach:
Form equation: (3k + 250) = 2*(2k) = 4k to solve for k, then compute tin = 2k.

Step-by-Step Solution:

Verification / Alternative check:
Original copper = 750 g, tin = 500 g; after +250 g copper → copper = 1000 g ⇒ 1000 = 2*500 (true).

Why Other Options Are Wrong:
250, 750, 1000 correspond to k or copper amounts; correct tin is 500 g.

Common Pitfalls:
Setting final ratio as 2:1 of total weight rather than copper to tin only.

Final Answer:
500