CBSE Class 12 Sample Paper for 2022 Boards (MCQ Based - for Term 1)
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CBSE Class 12 Sample Paper for 2022 Boards (MCQ Based - for Term 1)
Last updated at Dec. 16, 2024 by Teachoo
Transcript
Question 48 The most economical speed to run the train is: (a) 18 km/h (b)5 km/h (c) 80 km/h (d) 40 km/h We need to find minimise Cost Now, Cost = C(v) = 𝟑𝟕𝟓/𝟒 𝒗 + 𝟔𝟎𝟎𝟎𝟎𝟎/𝒗 Differentiating w.r.t v C’(v) = 𝟑𝟕𝟓/𝟒 − 𝟔𝟎𝟎𝟎𝟎𝟎/𝒗^𝟐 Putting C’(v) = 0 0 = 375/4 − 600000/𝑣^2 600000/𝑣^2 = 375/4 600000 ×4/375 = 𝑣^2 600000 ×4/375 = 𝑣^2 1600 × 4 = 𝒗^𝟐 40 × 2 = 𝒗 80 = 𝒗 𝒗 = 80 km/hr So, the correct answer is (c)
