A person walks up a stalled escalator in 90 sec. When standing on the same escalator now moving he is carried up in 60 sec. How much time would it take him to walk up on the morning escalator?
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Answered by
370
distance traveled = D
speed of escalator = D/60 units
speed of the person = D/90 units
total speed = D /60 + D/90 = D/36 units
Time if walks on moving escalator = D/ [D/36] = 36 sec.
speed of escalator = D/60 units
speed of the person = D/90 units
total speed = D /60 + D/90 = D/36 units
Time if walks on moving escalator = D/ [D/36] = 36 sec.
Answered by
72
Distance travelled is equal to D Therefore D = 90 × s1. As dist equal speed into time (let s1 be speed of man in stalled escalator) Also in second case D will remain same Then D= 60 × s2 (S2 be the speed of escalator) Then D=D 90 ×s1= 60 × s2 Therefore S1/S2= 2/3 Therefore s 1 and s2 are respectively 2 and 3 Now In second case Man will also travel + escalator also So, For speed of structure Which is equal to s1+s2 = 2+3=5m/s D= 90 × s1 D= 180m(as s1 equal 2) Then time = distance/speed T=180/5=36s So ,T= 36s.
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