Straight Line Question 151

Question: A light ray coming along the line $ 3x+4y=5 $ gets reflected from the line $ ax+by=1 $ and goes along the line $ 5x-12y=10 $ . Then

Options:

A) $ a=64/115,b=112/15 $

B) $ a=14/15,b=-8/115 $

C) $ a=64/115,b=-8/115 $

D) $ a=64/15,b=14/15 $

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Answer:

Correct Answer: C

Solution:

  • [c] $ ax+by=1 $ Will be one of the bisectors of the given line. Equations of bisectors of the given lines are $ \frac{3x+4y-5}{5}=\pm ( \frac{5x-12y-10}{13} ) $ Or $ 64x-8y=115 $ Or $ 14x+112y=15 $ Or $ a=\frac{64}{115},b=-\frac{8}{115} $ Or $ a=\frac{14}{15},b=\frac{12}{115} $