Income split and total constraint: Bina’s monthly income is 90% of Anita’s monthly income. The sum of their monthly incomes equals Mr. Sen’s monthly income. Mr. Sen’s annual income is ₹7,75,200. Find Bina’s monthly income.

Introduction / Context:
We relate three incomes: two individual monthly incomes whose sum equals a third person’s monthly income. The third person’s annual income is provided, so first convert it to monthly, then allocate between Anita and Bina according to the 90% relation.

Given Data / Assumptions:

• Mr. Sen’s annual income = ₹7,75,200 ⇒ monthly = 7,75,200 / 12 = ₹64,600.
• Bina = 90% of Anita ⇒ B = 0.9A.
• A + B = 64,600.

Concept / Approach:
Express B in terms of A and substitute into the sum to solve for A. Then compute B = 0.9A. This is a basic linear equation in one variable after substitution.

Step-by-Step Solution:

Verification / Alternative check:
Sum check: 34,000 + 30,600 = 64,600 equals Mr. Sen’s monthly income; annualizing 64,600 * 12 = 7,75,200 as given.

Why Other Options Are Wrong:

• ₹34,000 and ₹36,000: These are Anita’s or unrelated values, not Bina’s monthly income.
• ₹30,000: Slight underestimate; 90% of 34,000 is exactly ₹30,600.

Common Pitfalls:
Forgetting to convert annual to monthly, or misapplying the 90% to the combined income rather than to Anita’s income alone.

Final Answer: