Scoring percentage and total questions: A candidate answered 12 questions and scored full marks on them. If his overall score is 60% with all questions carrying equal marks, what is the total number of questions in the test?

Introduction / Context:
Equal-mark questions allow us to map the number of correct answers directly to a percentage of the total. If a candidate gets full marks on a certain count of questions, that count represents the percentage of the total corresponding to the overall score.

Given Data / Assumptions:

• The candidate attempted 12 and scored full marks on these 12.
• Overall percentage = 60% of the total possible marks.
• Each question carries the same marks; no negative marking is implied.

Concept / Approach:
Let total questions be T. Full marks on 12 questions equals 12/T of the total marks. Since his overall is 60%, we have 12/T = 0.60. Solve for T directly.

Step-by-Step Solution:
12 / T = 0.60T = 12 / 0.60 = 20

Verification / Alternative check:
If the test has 20 questions, 60% correct equals 12 questions. This aligns perfectly with “full marks in all of them.”

Why Other Options Are Wrong:
36, 30, 25, and 24 do not satisfy 12/T = 0.60 with T as an integer.

Common Pitfalls:
Interpreting “attempted” as including partially correct marks; the phrase “secured full marks in all of them” implies 12 fully correct questions mapping directly to 60%.

Final Answer:
20