Sonia travels to IBA from Uttara by car at a speed of 40 km per hour and returns to Uttara at a speed of 30 km per hour by an auto rickshaw. What is her average speed in the entire journey in km/hour?
A. 35
B. 34.3
C. 37.5
D. 35.3
E. 36
Explanation: Average speed \(= \frac{2uv}{u+v}\). Here \(u=40 \text{ kmph}\) and \(v=30 \text{ kmph}\). Average speed \(= \frac{2\times40\times30}{40+30} = \frac{2400}{70} \approx 34.3 \text{ kmph}\).
Related Questions (Any University/Year)
- A box in the university bookstore contains books and each book in the box is a History book. an English book or a and one -sixth are English books, what fraction of the books are Science books?
- Of a group of people surveyed in a political poll, 60 percent said that they would vote for candidate R. Of those who said they would vote for R. 90 percent actually voted for R. and of those who did not say that they would vote for R. 5 percent actually voted for R. What percent of the group voted for R?
- Average of 5 consecutive even numbers is 8 which is the smallest of the 5 number----.
- Sharif ran a 2 mile race at an average speed of 8 miles per hour. If arif ran the same race at an average speed of 6 miles per hr. How many minutes longer than sharif did arif take to complete the race?
- The length of a field i 1.5 times of it s width . If the width if this field is 20 meters. find out the cost of fencing the field at a cost of Tk. 5.0 per meter.
- Ajar contains 10 red marbles and 30 green ones .How many red marbles must be added to the jar so that 60% of the marbles will be red?
- Samantha went shopping and bought one red bag and 15 black bags. The cost of the red bag was 3 times the average cost of a black bag. If she had spent a total of Taka x for the bags, what was the cost of the red bag (in terms of x)
- The missing number in the bracket 21 (9) 12, 24 (?) 9 is
- ঢাকা থেকে চট্টগ্রামের দূরত্ব ২৪০ কি. মি.। একটি বাস ঘণ্টায় ৬০ কি. মি. গতিতে গিয়ে ঘণ্টায় ৪০ কি. মি. গতিতে ফিরে এল। বাসটির গড় গতিবেগ কত?
- The difference between two positive numbers is 16. If the smaller of those two numbers is 3/5th of the larger, what is the value of the smaller number?
- A vendor bought chocolate at 6 for a taka. How many for a taka must he sell to gain 20% ?
- If a doctor gives you 3 pills and tells you take one pill every half hour, how long would it be before all the pills had been taken?
- If x and y are integers, 13<x<25 and -2>y>-13, what is the greatest possible value of (x -y)?
- At a certain party attended by 32 people, 24 of them were students. If 12 of those in attendance were women, and if 6 of the women in attendance were students, then how many of the men who attended the party were NOT students?
- The minimum time Mr. and Mrs. Ahmed require to reach the market from their house by walking is 25 minutes and 20 minutes prospectively. If Mr. and Mrs . Ahmed decided to go to the market together by walking, what is the minimum time they will require to reach the market?
- বিশ্বকাপ ফুটবলে এশিয় অঞ্চলের সাতটি দল পরস্পরের সাথে খেললে মোট কয়টি ম্যাচ অনুষ্ঠিত হবে?
- A can complete a project in 20 days and B can complete the same project and B start working on the project together and A quits 10 days before in 30 days. If A the project is completed, in how many days will the project be completed?
- একটি ঝুড়িতে আপেল এবং কমলা মিলিয়ে ২১ টি ফল আছে।প্রতিটি আপেল ১৫ টাকা এবং কমলা ১৮ টাকা দামে কেনা হয়েছে।সবগুলো ফল কিনতে যদি ৩৪৮ টাকা খরফ হয় তবে আপেল এবং কমলার মোট দামের পার্থক্য কত?
- Mr. Karim traveled from A to B at a speed of 3 km/hr and returned from B to A at a speed of 5 km/hr. the round trip required 8 hours what was the distance between A and B in km?
- During a particular day, x number of applicants came to IBA to submit their applications before lunch. Of them 70% were male applicants. On the same day, y number of applicants came to submit their application after lunch and all of them were male applicants. On that particular day , the ratio of male applicants to female applicants was 4:1. Calculate y in terms of x.