A train traveling at a uniform speed for 360 Km would have taken 48 min less to travel the same distance if it, s speed were 5Km per hour's more find the original speed of the train
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Answered by
9
Let original speed of train = x km/h
we know,
time = distance/speed
first case
———————
time taken by train = 360/x hour
second case
——————————
time taken by train its speed increase 5 km/h = 360/( x + 5)
question says that
time taken by train in first - time taken by train in 2nd case = 48 min = 48/60 hour
360/x - 360/(x +5) = 48/60 = 4/5
360{ 1/x - 1/(x +5) } = 4/5
360 ×5/4 { 5/(x² +5x )} =1
450 x 5 = x² + 5x
x² +5x -2250 = 0
x = { -5±√(25+9000) }/2
=(-5 ±√(9025) )/2
=(-5 ± 95)/2
= -50 , 45
but x ≠ -50 because speed doesn't negative
so, x = 45 km/h
hence, original speed of train = 45 km/h
please mark as BRAINliest answer
we know,
time = distance/speed
first case
———————
time taken by train = 360/x hour
second case
——————————
time taken by train its speed increase 5 km/h = 360/( x + 5)
question says that
time taken by train in first - time taken by train in 2nd case = 48 min = 48/60 hour
360/x - 360/(x +5) = 48/60 = 4/5
360{ 1/x - 1/(x +5) } = 4/5
360 ×5/4 { 5/(x² +5x )} =1
450 x 5 = x² + 5x
x² +5x -2250 = 0
x = { -5±√(25+9000) }/2
=(-5 ±√(9025) )/2
=(-5 ± 95)/2
= -50 , 45
but x ≠ -50 because speed doesn't negative
so, x = 45 km/h
hence, original speed of train = 45 km/h
please mark as BRAINliest answer
Answered by
0
Answer:
Step-by-step explanation:
Let initial speed of train be x km/hr.
Distance travelled = 360 km.
//we know that Speed = Distance/time => Time = Distance /Speed.
Time taken by train Initially = 360/x.
If speed is increased by 5 km/hr,
Time taken by train = 360/x+5.
Difference in time taken = 48/60 hr.
=> 360/x - 360/x+5 = 48/60
=> 360(1/x - 1/x+5) = 48/60
=> 360[x + 5 - x / x(x+5)] = 48/60
=> 360 * 5/x(x+5) = 48/60
=> x(x+5) = 360 * 5 * 60 / 48
=> x² + 5x = 2250
=> x² + 5x - 2250 = 0
=> x² + 50x - 45x - 2250 = 0
=>x(x+50) - 45(x+50) = 0
=> (x - 45)(x + 50) = 0
=> x = 45 or -50.
Since x cannot be negative, x= 45 km/hr.
Thus original speed of train = 45 km/hr.
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