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
53 views
in Aptitude by (106k points)
closed by

A dolphin covers 14 Km along with current and 5 Km against the current in Bay of Bengal. It takes 7 hours in complete journey. Find the speed of current if the speed of dolphin in still water is 4 Kmph.


1. 3 km/hr
2. 2 km/hr
3. 1 km/hr
4. 1.8 km/hr

1 Answer

0 votes
by (106k points)
selected by
 
Best answer
Correct Answer - Option 1 : 3 km/hr

Calculation

Time taken by dolphin to cover 14 Km along with stream and 5 Km against stream is 7 hours

⇒ Speed of dolphin in still water = S= 4 Kmph

Let the speed of current be SW  = x

⇒ 14/(4 + x) + 5/(4 - x) = 7

⇒ 7x2 - 9x - 36 =0

On solving the equation, we get,

⇒ x = 3, reject x = – 12/7

∴ Speed of current is 3 Kmph.

Speed of upstream = speed of boat in still water - speed of current

Speed of downstream = speed of boat in still water + speed of current

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.

Categories

...