In an exam, 950 boys and 250 girls appeared. If 90% of the boys and 60% of the girls passed, what percentage of all candidates failed?

Introduction / Context:
This question tests aggregation of pass/fail percentages across groups of different sizes. Compute the total passes, subtract from total candidates, and express the failures as a percentage of the total.

Given Data / Assumptions:
Appeared: boys = 950, girls = 250. Pass rates: 90% of boys, 60% of girls.

Concept / Approach:
Calculate passes separately by group, sum to get total passes, subtract from total candidates to get failures, and finally convert to a percentage of total appeared.

Step-by-Step Solution:

Verification / Alternative check:
Passed % = 1005/1200 * 100 = 83.75%; hence failed % = 100 − 83.75 = 16.25%.

Why Other Options Are Wrong:
16.50% and 16.75% are close distractors, but exact arithmetic yields 16.25%.

Common Pitfalls:
Rounding early or using the average of 90% and 60% without accounting for different group sizes.

Final Answer:
16.25%