Started 3 weeks ago by Samiksha Agnihotri in
3 Replies
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Replied 2 months ago
Total distance = 105 km in 5 hoursS5 = S1ยฒ + 15S3 = S5/2S4 = 2(S1 + S2)S2 = S3/2Setting up the equations:From the relationships:S2 = S3/2S3 = S5/2Therefore: S2 = (S5/2)/2 = S5/4Since S5 = S1ยฒ + 15:S3 = (S1ยฒ + 15)/2S2 = (S1ยฒ + 15)/4And S4 = 2(S1 + S2) = 2(S1 + (S1ยฒ + 15)/4) = 2S1 + (S1ยฒ + 15)/2Using the constraint that the automobile covers 105 km in 5 hours:Since the speeds change at four different points with equal intervals, each speed is maintained for 1 hour.So: S1(1) + S2(1) + S3(1) + S4(1) + S5(1) = 105Substituting: S1 + (S1ยฒ + 15)/4 + (S1ยฒ + 15)/2 + 2S1 + (S1ยฒ + 15)/2 + (S1ยฒ + 15) = 105Simplifying: S1 + 2S1 + (S1ยฒ + 15)/4 + (S1ยฒ + 15)/2 + (S1ยฒ + 15)/2 + (S1ยฒ + 15) = 1053S1 + (S1ยฒ + 15)(1/4 + 1/2 + 1/2 + 1) = 1053S1 + (S1ยฒ + 15)(2.25) = 1053S1 + 2.25S1ยฒ + 33.75 = 1052.25S1ยฒ + 3S1 - 71.25 = 0Multiplying by 4: 9S1ยฒ + 12S1 - 285 = 0Using the quadratic formula: S1 = (-12 ยฑ โ(144 + 10260))/18 = (-12 ยฑ โ10404)/18 = (-12 ยฑ 102)/18Since speed must be positive: S1 = 90/18 = 5 km/hFinding all speeds:S1 = 5 km/hS2 = (25 + 15)/4 = 10 km/hS3 = (25 + 15)/2 = 20 km/hS4 = 2(5 + 10) = 30 km/hS5 = 25 + 15 = 40 km/hVerification: 5 + 10 + 20 + 30 + 40 = 105 kmย Answer: For continuous travel at S5 = 40 km/h to cover 105 km: Time = Distance/Speed = 105/40 = 2.625 hours.
Replied 2 weeks ago
explain please An automobile changes speed at four different points placed at equal intervals and covers 105 km in 5 hours S1,S2,S3.S4 and S5 are the 5 different speeds. S5 is 15 more than the square of S1, half of S5 is S3 , S4 is twice the sum of S1 and S2 and S2 makes up half of S3. How many hours of continuous travel will S5 require?
Replied 2 weeks ago
explain please An automobile changes speed at four different points placed at equal intervals and covers 105 km in 5 hours S1,S2,S3.S4 and S5 are the 5 different speeds. S5 is 15 more than the square of S1, half of S5 is S3 , S4 is twice the sum of S1 and S2 and S2 makes up half of S3. How many hours of continuous travel will S5 require?