a man completed a trip of 136 km in 8 hours some parts of the trip was covered at 15 km per hour and the remaining at 18 kilometre per hour find the path of trip covered at 18 kilometre per hour
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A man completed a trip of 136 km in 8 hours.
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asked May 24, 2019 in Class VIII Maths by aditya23 (-2,138 points)
A man completed a trip of 136 km in 8 hours. Some part of the trip was covered at 15 km/hr and the remaining at 18 km/hr. Find the part of the trip covered at 18 km/hr.
linear equations in one variable (with problems based on linear equations)
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answered May 24, 2019 by muskan15 (-3,440 points)
Total distance of the trip = 136 km
Let part of the trip covered at 18km/hr = x km
∴ Distance of the trip covered at 15km/hr = (136 – x) km
Time taken by the man to cover x km
= Distance/speed = (x/18) hours
Time taken by the man to cover (136 – x) km
= (136 – x)/15 hours
Total time taken by the man to cover a trip of 136 km = 8 hours
∴ x/18 + (136 – x)/15 = 8
⇒ x/18 × 90 + (136 – x)/15 × 90 = 8 × 90
[Multiplying each term by 90 because L.C.M. of denominators = 90]
⇒ 5x + 6 (136 – x) = 720
⇒ 5x + 816 – 6x = 720
⇒ 5x – 6x = 720 – 816
⇒ -x = -96
⇒ x = 96
∴ Part of the trip covered at 18km/ hr = 96 km