Let the total distance be y km.
Then, 2y / 5 = 1200
? y = (1200 x 5) /2 = 3000 km.
Distance traveled by car
= (1/3 X 3000) = 1000 km.
Distance traveled by train
= [3000- (1200 + 1000) ] km.
= 800 km.
Let distance covered by dog in 1 leap is x and
Distance covered by cat in 1 leap is y
Then, 3x = 4y
? x= 4/3y
Now, Ratio of speed of dog and cat = Ratio of distance covered by them in the same time = 4x : 5y
= 16/3y : 5y
= 16 : 15
Let the distance = x
Here, the difference in time
= 20 - 5 = 15 min
= 15/60 = 1/4h
Speed during next journey
= 15 + 5 = 20 km/h
According to the question,
x/15 - x/20 = 1/4
? 4x - 3x/60 = 1/4
? x = 60/4 = 15
? x = 15 km
Distance of his office from his house = {ab/(b - a)} x (t1 + t2)
Here, a = 20 km/h, t1 = 1 h, b = 20 + 5 = 25 km/h
and t2 = 30 min = 0.5 h
? Distance = {20 x 25/(25 - 20)} x (1 + 0.5) = 500(1.5)/5
= 100 x 1.5 = 150 km
Let total distance be 100 km.
Then, Average = 100/[ (50/40) + (30/60) + (20/30)]
= 100/( 5/4 + 1/2 + 2/3) = 100/[(15 + 6 + 8)/12]
= (100 x 12)/29
= 42.35
Let B catches A after T h.
Then, distance travelled by A in (T + 2) h = Distance travelled by B in T h
According to the question,
2 (T + 2 ) = 5T
? 2T + 4 = 5T
? 3T = 4
? T = 4/3 h
Distance travelled by B in 4/3 h
= (4/3) x 5 = 20/3 = 62/3 km
Relative velocity = u + v = 18 + 20 = 38 km
They are 38 km. apart in 1 hr.
? They will be 95 km. apart in ( 95 / 38) hrs.
= 2 hrs . 30 min
Distance left = (1/2 x 80 ) km. = 40km.
Time left - [(1-3/5) x 10 ] hrs.
= 4 hours
Required speed = (40 / 4 ) km/hr
= 10 km/hr.
Ratio of times taken by A and B = 1/2 : 1/3
Suppose B takes Tb min. Then A takes (Tb + 10) min.
? (Tb + 10 ) : Tb = 1/2: 1/3
? (Tb + 10)/Tb = 3 / 2
? 2Tb + 20 = 3Tb
? Tb = 20
? Time taken by A = 20 +10
= 30 minute
If A had walked at double speed
Req . time = 30/2
=15 minute
Suppose the man covers first distance in x hrs and second distance in y hrs.
Then, 4x + 5y = 35 and 5x + 4y = 37
Solving these equations, we get
x = 5 and y = 3
? Total time taken = 5 + 3 hrs.
= 8 hrs.
Let the required time = T min.
Then, distance covered in T + 11 min at 40 km/hr = distance covered in T + 5 min at 50 km/hr.
? 40 ( T + 11 ) / 60 = 50 (T + 5 ) / 60
? T = 19 min.
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