In a certain coded arithmetic, the symbols represent different operations: 'X' means addition (+), '-' means division (/), '/' means subtraction (-), and '+' means multiplication (*). Based on this decoding, which of the following coded equations is mathematically correct?

Introduction / Context:
This question tests operator substitution and equation validation. The expression uses symbols that do not represent their usual operations. You must decode each equation and check which one becomes true under standard arithmetic rules.

Given Data / Assumptions:

• X means addition (+).
• - means division (/).
• / means subtraction (-).
• + means multiplication (*).
• After decoding, use standard precedence (*/ before + and -).

Concept / Approach:
Pick one option at a time, replace each operator with its decoded meaning, then compute the left-hand side. The correct coded equation is the one whose decoded left-hand side equals the right-hand side exactly.

Step-by-Step Solution:
Check option A: 25+10-5/10X3=43 Decode: + becomes *, - becomes /, / becomes -, X becomes + So LHS becomes: 25 * 10 / 5 - 10 + 3 Compute: 25 * 10 = 250 250 / 5 = 50 50 - 10 + 3 = 43 Decoded LHS equals RHS (43). So option A is correct.

Verification / Alternative check:
Notice that 25 * 10 / 5 simplifies neatly: it is (25/5)*10 = 5*10 = 50, then 50 - 10 + 3 = 43. This confirms the equality without lengthy work.

Why Other Options Are Wrong:
Option B: after decoding, the arithmetic does not evaluate to 72. Option C: decoding changes the structure; it will not match 12 under correct precedence. Option D: becomes a different numeric value than 18 when computed correctly. Option E: is a distractor and does not decode to 40.

Common Pitfalls:
Using the printed symbols as normal, decoding only one or two operators, or performing addition/subtraction before division/multiplication in the decoded equation leads to incorrect selection.

Final Answer:
25+10-5/10X3=43