In a ∆ ABC, ∠A + ∠B = 75° and ∠B + ∠C

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In a ∆ ABC, ∠A + ∠B = 75° and ∠B + ∠C = 140°, then ∠B is

1. 40°
2. 35°
3. 55°
4. 45°

Correct Option: B

Given that , ∠A + ∠B = 75° and ∠B + ∠C = 140°
In ∆ ABC,
We know that , ∠A + ∠B + ∠C = 180°
∴ ∠B = (∠A + ∠B + ∠B + ∠C) – (∠A + ∠B + ∠C)
∠B = 75° + 140° – 180° = 35°