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  1. If sin (3x – 20°) = cos (3y + 20°), then the value of (x + y) is
    1. 20°
    2. 30°
    3. 40°
    4. 45°
Correct Option: B

sin(3x – 20°)
= cos (3y + 20°)
⇒ sin (3x – 20°)
= sin(90° – 3y – 20°)
= sin(70° – 3y)
⇒ 3x – 20° = 70° – 3y
⇒ 3x + 3y = 90°
⇒ 3(x + y) = 90°
⇒ x + y = 30°



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