Advertisements
Advertisements
प्रश्न
Choose the most appropriate option.
A boat travels upstream from A to B and back from B to A in 5 hours. The speed of the boat in still water is 8 km/hour and the speed of the current is 4 km/hour. Then, the distance from A to B is:
विकल्प
9 kms.
10 kms.
15 kms
12 kms
Advertisements
उत्तर
15 kms
Explanation:
Speed of the boat in still water = 8 km/hr
Speed of the current = 4 km/hr
∴ Speed downstream = 8 + 4 = 12 km/hr
Speed upstream = 8 − 4 = 4 km/hr
Let the distance between A and B be x.
Then,
`"x"/12+"x"/4=4` `("x"+3"x")/12=5`
`∴(4"x")/12=5`
`∴"x"=(12xx5)/4=15` km
APPEARS IN
संबंधित प्रश्न
Ranjeetha walks around the circular park in 15 minutes. If she walks at the rate of 5 km/hr, how much distance would she have to travel, at the minimum, to reach the centre of the park from any point on its perimeter?
Azhar can row 9.333 kmph in still waters and finds that it takes him thrice as much time to row up than as to row down the same distance in the river. The speed of the current of the river is
The Bubna dam has four inlets. Through the first three inlets, the dam can be filled in 12 minutes; through the second, the third and the fourth inlet, it can be filled in 15 minutes; and through the first and the first inlet, in 20 minutes. How much time will it take all the four inlets to fill up the dam?
120 men had food provision for 200 days. After 5 days, 30 men died of an epidemic. The food will last for further
Two trains of equal length are running on parallel lines in the same direction at 46 km/h and 36 km/h. The faster train passes the slower train in 36 s. The length of each train is
Two trains running in opposite directions cross a man standing on the platform in 27 sec and 17 sec, respectively and they cross each other in 23 sec. The ratio of their speeds is
A car completes a certain journey in 8 h. It covers half the distance at 40 km/h and the rest at 60 km/h. The length of the journey is
P and Qare towns. A man drives from P to Q at an average speed of 50 km/h. He stop at Q for 4 hours and then heads back to P at an average speed of 40 km/h following the same route. What is his average speed (in km/ h correct to two decimal places) if he takes 22 hours for the entire trip?
A man crosses a road 250 metres wide in 75 seconds. His speed in km/hr is :
A train travels 500 m in first minute. ln the next 4 minutes, it travels in each minute 125 m more than that in the previous minute. The average speed per hour of the train during those 5 minutes will be
