Discussion
A boat covers 30 km upstream and 44 km downstream in 10 hours, and 40 km upstream and 55 km downstream in 13 hours. What is the speed of the stream ?
Answer: C
Correct answer: 3 km/hr
Write \(p = \tfrac{1}{u}\) and \(q = \tfrac{1}{d}\), which makes both conditions linear.
\[30p + 44q = 10, \qquad 40p + 55q = 13\]
Multiplying the first by 4 and the second by 3 and subtracting gives \(11q = 1\), so \(d = 11\) km/hr. Substituting back, \(30p = 6\), so \(u = 5\) km/hr.
\[s = \frac{11 - 5}{2} = 3 \text{ km/hr}\]
No comment is present. Be the first to comment.
Loading…
Post your comment
Please log in or register to post a comment.
Examination Categories
- SSC Exams
- Banking Exams
- Teaching Exams
- Civil Services Exams
- Railways Exams
- Engineering Recruitment Exams
- Defence Exams
- State Government Exams
- Police Exams
- Insurance Exams
- Nursing Exams
- Other Government Exams
- NRA CET
- PG Entrance Exams
- Campus Placement
- MBA Entrance Exams
- CUET and UG Entrance
- Judiciary Exams
- Regulatory Body Exams
- Software Development