In a school with 1500 boys, 35% are Hindus, 30% are Sikhs, 15% are Muslims and the remaining are Christians. How many Christian boys are there in the school?

Introduction / Context:
This question is a straightforward percentage distribution problem. The total number of boys in a school is given, along with the percentage distribution across different religious groups. We are asked to find how many boys belong to the Christian group, which is the remaining percentage after accounting for the other groups.

Given Data / Assumptions:

• Total number of boys in the school = 1500.
• 35% of the boys are Hindus.
• 30% of the boys are Sikhs.
• 15% of the boys are Muslims.
• The remaining boys are Christians.
• We assume the percentages cover all boys exactly.

Concept / Approach:
The central idea is that the sum of all percentage groups must be 100%. First, we add the given percentages for Hindus, Sikhs and Muslims to find their combined share. Then we subtract this sum from 100% to get the percentage of Christian boys. Finally, we apply this percentage to the total number of boys to find the required count. This is a typical application of percentage and complementary values in basic arithmetic.

Step-by-Step Solution:
Step 1: Total boys = 1500. Step 2: Percentage of Hindu boys = 35%. Step 3: Percentage of Sikh boys = 30%. Step 4: Percentage of Muslim boys = 15%. Step 5: Combined percentage of Hindu, Sikh and Muslim boys = 35% + 30% + 15% = 80%. Step 6: Since all boys must belong to one of these groups, the percentage of Christian boys = 100% - 80% = 20%. Step 7: Number of Christian boys = 20% of 1500 = 0.20 * 1500. Step 8: Compute 0.20 * 1500 = 300. Step 9: Therefore, there are 300 Christian boys in the school.

Verification / Alternative check:
We can check by computing the number in each group. Hindu boys = 35% of 1500 = 525. Sikh boys = 30% of 1500 = 450. Muslim boys = 15% of 1500 = 225. Christian boys (if 300) give a total of 525 + 450 + 225 + 300 = 1500, which matches the total boys given. Hence the distribution is consistent and the answer is correct.

Why Other Options Are Wrong:
If there were 250 or 200 Christian boys, the total count after adding all religious groups would be less than 1500. If there were 350 Christian boys, the total would exceed 1500. Therefore, only 300 satisfies both the percentage and total count conditions.

Common Pitfalls:
Students sometimes incorrectly add percentages as 35 + 30 + 15 + required = 1500, confusing percentage values with absolute counts. Another frequent error is to mistakenly take the Christian percentage as one of the listed numbers rather than computing it as the complement of the sum of the other percentages. Always remember that percentages should sum to 100% when all groups are included.

Final Answer:
The number of Christian boys in the school is 300.