The following table represents the total number of students in different classes and the respective number of students who are vegetarian, in a school. Study the table carefully and answer the question that follows. Class → Total number of students | Number of vegetarian students XII — 150 | 105 XI — 165 | 100 X — 125 | 80 IX — 140 | 90 What is the percentage of non-vegetarian students in class XII?

Correct — A. The table prints vegetarian students, so the non-vegetarian count has to be built before any percentage.

Class XII row: total = 150, vegetarian = 105.
Non-vegetarian = 150 − 105 = 45

Percentage = (45 ÷ 150) × 100
= 0.3 × 100 = 30% → option (a).

Cross-check: 105 ÷ 150 = 70% vegetarian, and 100% − 70% = 30%.

Why the others are wrong

• (b)
  35% — 35% of 150 is 52.5 students, which no headcount can be. The class XII row gives exactly 45 non-vegetarian students, and 45 out of 150 is 30%.
• (c)
  25% — 25% of 150 is 37.5 students, again not a whole number. It also treats the vegetarian share as 75% when the row gives 105 out of 150, which is 70%.
• (d)
  40% — 40% would need 60 non-vegetarians, leaving only 90 vegetarians. 90 is the vegetarian figure in the class IX row; class XII shows 105.

Table DI rewards reading the column headings before touching the arithmetic.

This table supplies total students and vegetarian students. Any non-vegetarian question is therefore a subtraction first and a percentage second.

Percentage of a part = (part ÷ whole) × 100, and the whole is the class total in the same row — never the school total.

Because vegetarian and non-vegetarian exhaust the class, the two percentages of a row must add to 100%. That gives a free check on every answer.

Key facts

• Class XII has 150 students of whom 105 are vegetarian, leaving 45 non-vegetarian.
• 45 out of 150 is 30%, and the matching vegetarian share is 70%.
• In a two-category row the part percentages always sum to 100%, so one subtraction replaces a second division.

Common traps

• Answering 70%, the vegetarian share, because that is the number actually printed.
• Dividing by the school total instead of the 150 in the class XII row.
• Picking up the class XI figures 165 and 100 when the question names class XII.

No directly related past PYQ was found.