Use app×
Join Bloom Tuition
One on One Online Tuition
JEE MAIN 2025 Foundation Course
NEET 2025 Foundation Course
CLASS 12 FOUNDATION COURSE
CLASS 10 FOUNDATION COURSE
CLASS 9 FOUNDATION COURSE
CLASS 8 FOUNDATION COURSE
0 votes
1.2k views
in Distance, Time and Speed by (49.2k points)
closed by

A boat running upstream takes 8 hours 48 min to cover a certain distance, while it takes 4 hours to cover the same distance running downstream. What is the ratio between the speed of the boat and the speed of the water current respectively? 

(a) 2 : 1 

(b) 3 : 1 

(c) 8 : 3 

(d) 4 : 3

1 Answer

+1 vote
by (46.1k points)
selected by
 
Best answer

(c) 8 : 3

Let the distance covered in one direction be x km. 

Then, speed upstream = \(\frac{x}{\frac{44}{5}}\) km/hr

(8 hrs 48 min = \(8\frac{48}{60}=8\frac45\) hrs) = \(\frac{5x}{44}\) km/hr

Speed downstream =\(\frac{x}4\) km/hr

∴ Speed of boat in still water = \(\frac12\bigg(\frac{5x}{44}+\frac{x}{4}\bigg)\)

\(\frac{8x}{44} = \frac{2x}{11}\) km/hr

Speed of current = \(\frac12\bigg(\frac{x}{4}-\frac{5x}{44}\bigg)=\frac{3x}{44}\) km/hr

∴ Required ratio = \(\frac{2x}{11}:\frac{3x}{44}=8:3.\)

Welcome to Sarthaks eConnect: A unique platform where students can interact with teachers/experts/students to get solutions to their queries. Students (upto class 10+2) preparing for All Government Exams, CBSE Board Exam, ICSE Board Exam, State Board Exam, JEE (Mains+Advance) and NEET can ask questions from any subject and get quick answers by subject teachers/ experts/mentors/students.

...