Vedadots
Q5556/80Q57
Q56·CSAT · Prelims 2025

Comparative - maximum value of p x q

DI / DSComparative QuantitativeComparative quantitativeMedium

Question

Let p + q = 10, where p, q are integers. Value-I = Maximum value of p × q when p, q are positive integers. Value-II = Maximum value of p × q when p ≥ -6, q ≥ -4. Which one of the following is correct?

Options

a

Value-I < Value-II

b

Value-II < Value-I

c

Value-I = Value-II

Answer
d

Cannot be determined due to insufficient data

Explanation

We need to maximize p × q given p + q = 10. For Value-I, p and q are positive integers. The product of two numbers with a constant sum is maximized when the numbers are as close to each other as possible. Thus, p=5 and q=5, yielding a max product of 25. For Value-II, the constraints are p \ge -6 and q \ge -4. The unconstrained maximum occurs at p=5, q=5. Since these values perfectly satisfy the boundary conditions (5 \ge -6 and 5 \ge -4), the maximum product remains exactly 25.

For a fixed sum A + B = K, the product A × B forms a downward-opening parabola peaking exactly at A = B = K/2.

Answer: (c).

Question details

Year

2025

Paper

CSAT

Question

Q56

Section

Data Interpretation & Sufficiency

Sub-topic

Comparative Quantitative

Type

Comparative quantitative

Difficulty

Medium

Source hint

Quantitative comparison

Same sub-topic — other years

Comparative Quantitative has appeared in multiple CSAT papers:

See all questions on Comparative Quantitative

Browse every tagged question across all years

Explore →