A motor boat goes down stream 30km and again returns to the starting point
in a total time of 4 hours and 30 minutes. If the speed of the stream is 15km/hr,
then find the speed of the motor boat in still water.
Share
A motor boat goes down stream 30km and again returns to the starting point
in a total time of 4 hours and 30 minutes. If the speed of the stream is 15km/hr,
then find the speed of the motor boat in still water.
Sign Up to our social questions and Answers Engine to ask questions, answer people’s questions, and connect with other people.
Login to our social questions & Answers Engine to ask questions answer people’s questions & connect with other people.
Verified answer
Step-by-step explanation:
Let the speed of the stream be x km/hr
Speed downstream =(15+x)km/hr
Speed upstream =(15−x)km/hr
Distance travelled downstream=30km
Distance travelled upstream=30km
Time upstream=
Speed upstream
Distance upstream
Time upstream=
15−x
30
Time downstream=
Speed downstream
Distance downstream
Time downstream=
15−x
30
Total time taken 4.5hrs
4.5=
15−x
30
+
15+x
30
4.5=
225−x
2
30(15+x)+30(15−x)
4.5=
225−x
2
900
225−x
2
=200
x
2
=25
x=5km/hr