If a \(600 \ meter\) long train crossed a \(120 \ meter\) long platform in \(20 \ seconds\), then find the speed of the train?
\(30 \ m/sec\)
\(32 \ m/sec\)
\(36 \ m/sec\)
\(38 \ m/sec\)
Answer: (c) \(36 \ m/sec\)Solution: Given, length of the train \((l_m) = 600 \ meter\)length of the platform \((l_s) = 120 \ meter\)time taken by the train to cross the platform \((T) = 20 \ seconds\), then $$ Time \ taken \ (T) = \frac{l_m + l_s}{s_m} $$ $$ 20 = \frac{600 + 120}{s_m} $$ $$ s_m = \frac{720}{20} = 36 \ m/sec $$
A man goes from Bhopal to Nagpur at the speed of \(100 \ km/hr\) and returns. If the average speed of the man during the whole journey is \(80 \ km/hr\), then find the speed of the man when returns from Nagpur to Bhopal?
\(65.25 \ km/hr\)
\(66.67 \ km/hr\)
\(68.58 \ km/hr\)
\(68.21 \ km/hr\)
Answer: (b) \(66.67 \ km/hr\)Solution: Given, speed of the man when travels from Bhopal to Nagpur \((s_1) = 100 \ km/hr\)Average speed of the man = \(80 \ km/hr\)Let the distance between Bhopal and Nagpur = \(1 \ km\), then $$ Average \ speed = \frac{distance \ covered}{time \ taken} $$ $$ Average \ speed = \frac{d_1 + d_2}{\frac{d_1}{s_1} + \frac{d_2}{s_2}} $$ $$ 80 = \frac{1 + 1}{\frac{1}{100} + \frac{1}{s_2}} $$ $$ 80 = \frac{2 \times 100 \times s_2}{(s_2 + 100)} $$ $$ 80 \ s_2 + 8000 = 200 \ s_2 $$ $$ s_2 = \frac{8000}{120} = 66.67 \ km/hr $$
A women travels from city A to city B with the initial speed of \(30 \ km/hr\) and increases the speed \(50 \ km/hr\) with the rate of acceleration \(10 \ km/hr\), then find the time taken by the women to achieve the final speed?
\(2 \ hours\)
\(3 \ hours\)
\(4 \ hours\)
\(5 \ hours\)
Answer: (a) \(2 \ hours\)Solution: Given, initial speed of the women \((V_i) = 30 \ km/hr\)final speed of the women \((V_f) = 50 \ km/hr\)Acceleration \((a) = 10 \ km/hr\), then $$ Acceleration \ (a) = \frac{V_f - V_i}{T} $$ $$ 10 = \frac{50 - 30}{T} $$ $$ T = \frac{20}{10} = 2 \ hours $$
Two \(200 \ meter\) and \(300 \ meter\) long trains, moving in the same direction with the speed of \(150 \ m/sec\) and \(x \ m/sec\) respectively. If faster train will pass the slower train in \(10 \ seconds\), then find the value of x?
\(105 \ m/sec\)
\(100 \ m/sec\)
\(110 \ m/sec\)
\(112 \ m/sec\)
Answer: (b) \(100 \ m/sec\)Solution: Given, length of the first train \((l_1) = 200 \ meter\)length of the second train \((l_2) = 300 \ meter\)speed of the first train \((s_1) = 150 \ m/sec\)speed of the second train \((s_2) = x \ m/sec\)time taken by the faster train to pass the slower train \((T) = 10 \ seconds\), then $$ Time \ taken \ (T) = \frac{l_1 + l_2}{s_1 - s_2} $$ $$ 10 = \frac{200 + 300}{150 - x} $$ $$ 1500 - 10 \ x = 500 $$ $$ x = 100 \ m/sec $$
Two trains are moving towards each other with the speed of \(700 \ m/sec\) and \(800 \ m/sec\) respectively. If the length of the first train is \(2600 \ meter\), then find time taken by the first train to cross the second train, where as the length of the second train is not considered?
\(1.73 \ seconds\)
\(1.25 \ seconds\)
\(2.35 \ seconds\)
\(2.37 \ seconds\)
Answer: (a) \(1.73 \ seconds\)Solution: Given, speed of the first train \((s_1) = 700 \ m/sec\)speed of the second train \((s_2) = 800 \ m/sec\)length of the first train \((l_1) = 2600 \ meter\), then $$ Time \ taken \ (T) = \frac{l_1}{s_1 + s_2} $$ $$ = \frac{2600}{700 + 800} $$ $$ T = 1.73 \ seconds $$
A girl travels on car with the initial speed of \(100 \ m/sec\) and accelerated with \(10 \ m/sec\) after \(15 \ seconds\) the girl achieved final speed. Find the final speed of the car?
\(220 \ m/sec\)
\(260 \ m/sec\)
\(250 \ m/sec\)
\(270 \ m/sec\)
Answer: (c) \(250 \ m/sec\)Solution: Given, initial speed of the car \((V_i) = 100 \ m/sec\)time taken by the car to achieve the final speed \((T) = 15 \ seconds\)acceleration rate of the car \((a) = 10 \ m/sec\), then $$ Acceleration \ (a) = \frac{V_f - V_i}{T} $$ $$ 10 = \frac{V_f - 100}{15} $$ $$ V_f = 250 \ m/sec $$
A boat goes downstream with the speed of \(55 \ km/hr\). If the speed of the boat in still water is \(35 \ km/hr\), then find the speed of stream?
\(15 \ km/hr\)
\(18 \ km/hr\)
\(20 \ km/hr\)
\(25 \ km/hr\)
Answer: (c) \(20 \ km/hr\)Solution: Given, speed of downstream \((D_s) = 55 \ km/hr\)speed of the boat in still water \((B_s) = 35 \ km/hr\), then $$ B_s = D_s - S_s $$ $$ 35 = 55 - S_s $$ $$ S_s = 20 \ km/hr $$
If the boat goes \(30 \ km\) upstream and \(40 \ km\) downstream, taking \(2 \ hours\) each time, then find the speed of the boat in still water?
\(17.5 \ km/hr\)
\(15.5 \ km/hr\)
\(20.5 \ km/hr\)
\(12.5 \ km/hr\)
Answer: (a) \(17.5 \ km/hr\)Solution: Given, speed of upstream \((U_s) = \frac{30}{2} = 15 \ km/hr\)speed of downstream \((D_s) = \frac{40}{2} = 20 \ km/hr\)then the speed of the boat in still water, $$ B_s = \frac{D_s + U_s}{2} $$ $$ = \frac{15 + 20}{2} $$ $$ = \frac{35}{2} = 17.5 \ km/hr $$
A boat goes upstream from point A to point B, taking \(4 \ hours\) and returns downstream from point B to point A. If the speed of stream is \(20 \ km/hr\) and speed of the boat in still water is \(40 \ km/hr\), then find the distance between point A and B?
\(80 \ km\)
\(70 \ km\)
\(60 \ km\)
\(50 \ km\)
Answer: (c) \(60 \ km\)Solution: Given, speed of the stream \((S_s) = 20 \ km/hr\)speed of the boat in still water \((B_s) = 40 \ km/hr\), thenspeed of upstream \((U_s) = B_s - S_s\) \(= 40 - 20 = 20 \ km/hr\)speed of downstream \((D_s) = B_s + S_s\) \(= 40 + 20 = 60 \ km/hr\)Let the distance between point A and B = \(x \ km\), then $$ \frac{x}{60} + \frac{x}{20} = 4 $$ $$ \frac{x + 3 \ x}{60} = 4 $$ $$ x + 3 \ x = 240 $$ $$ x = 60 \ km $$
Time Speed and Distance
Time Speed and Distance Aptitude Questions with Solution