NDA 2022 Maths · Mathematics · Straight Lines · medium

The product of the slopes of any two perpendicular lines is -1. 2. The lines 2x+3y=5 and 4x+6y=11 are parallel.

Single correct option

Which of the following statements is/are correct?
1. The product of the slopes of any two perpendicular lines is

-1

.
2. The lines

2x+3y=5

and

4x+6y=11

are parallel.

Show answer and solution

Answer: (B) $2$ only

Statement 1 fails for a vertical line and a horizontal line, which are perpendicular but the vertical line has no slope. Statement 2: both have slope

-\frac23

and they are distinct (not coincident since

\frac{4}{2}\ne\frac{11}{5}

), so they are parallel. Only Statement 2 is correct.

Original question written in the NDA 2022 Maths pattern and checked twice for the correct answer. Not an official question paper. How we write and check questions · Corrections policy · Report a mistake