Form an equation from wording: A number exceeds 20% of itself by 40. What is the number?

Introduction / Context:
We are told that a number is larger than 20% of itself by a fixed amount. This translates directly into a simple linear equation in one variable.

Given Data / Assumptions:

• x is the unknown number.
• x − 20% of x = 40.

Concept / Approach:
Convert the percent to decimal, collect like terms, and solve. This is equivalent to finding the value whose 80% equals 40.

Step-by-Step Solution:

Verification / Alternative check:
Compute 20% of 50 = 10; then 50 exceeds 10 by 40 — matches the condition exactly.

Why Other Options Are Wrong:

• 60, 80, 320, 200 do not satisfy x − 0.20x = 40 when substituted.

Common Pitfalls:
Mistaking “exceeds 20% of itself by” as “is 20% of itself plus 20%” or similar misreads. Carefully translate the sentence.

Final Answer:
50