CSATPercentage, Profit & LossPercentage Arithmetic2021

P scored 40 marks more than Q in an examination. If Q scored 10% less marks than P, then how much did Q score ?

A

360

B

380

C

400

D

420

Correct Answer: Option A

Explanation

We will solve this using the 'Gap Method' which was a core theme in the 2019 marks question [48].\n\n1. **Identify the Gap:** \n - The question tells us P scored 40 marks more than Q. So, the gap between them is **40 marks**.\n - It also tells us Q scored 10% less than P. This means the gap is **10% of P** [44].\n\n2. **Equate Difference to Percentage:**\n - Since both values represent the same gap, we can directly say: **10% of P = 40 marks**. \n - This is the 'Direct Mapping' technique seen in PYQs [45].\n\n3. **Find the Base (P):**\n - If 10% of P is 40, then 100% of P (the full value) is simply 10 times that amount.\n - P = 40 × 10 = **400 marks**.\n\n4. **Find the Answer (Q):**\n - The question asks for Q's score.\n - Since Q is 40 marks less than P: Q = 400 - 40 = **360**.\n\n**Sanity Check with Options:**\n - Let's check Option (A) 360.\n - If Q = 360, then P must be 400 (since P is 40 more).\n - Is 360 10% less than 400? Yes, 10% of 400 is 40, and 400 - 40 = 360. The logic holds perfectly.

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