Question : A girl goes from M to N at a speed of 25 km/hr and returns to M at a speed of 37.5 km/hr, via the same route. What is the girl's average speed (in km/hr)?
Option 1: 30
Option 2: 32
Option 3: 31.25
Option 4: 27.5
Correct Answer: 30
Solution :
Given:
$s_1$ = 25 km/hr
$s_2$ = 37.5 km/hr
Using the average speed formula
Average speed = $\frac{2 {s_1}{s_2}}{s_1 + s_2}=\frac{2\times 25\times 37.5}{25+37.5}
= 30$ km/hr
Hence, the correct answer is 30.
Related Questions
Know More about
Staff Selection Commission Multi Tasking ...
Application | Cutoff | Selection Process | Preparation Tips | Eligibility | Exam Pattern | Admit Card
Get Updates BrochureYour Staff Selection Commission Multi Tasking Staff Exam brochure has been successfully mailed to your registered email id “”.