In a flight of 600 km , an aircraft was slowed down due to bad weather. Its average speed for the trip was reduced by \(200~km/hr\) and the time of flight consequently increased by 30 minutes. The duration of the flight was:
A. 1 hour
B. 1.5 hours
C. 2 hours
D. 2.5 hours
Explanation: Let, speed be S and time be T. Now, \(ST=600\). Again, \((S-200)*(T+0.5)=600\). Or, \(ST - 200T + 0.5S - 100 = 600\). Or, \(200T - 0.5S + 100 = 0\). Or, \(200 T^2 + 100 T - 300 = 0\); \([S=600/T]\). Or, \(2T^2 + T - 3 = 0\). Or, \((2T+3)(T-1)=0\). Or, \(T = -3/2, 1\). So, flight টির duration ছিলো \(1 + 0.5\) hours = \(1.5\) hours.
Related Questions (Any University/Year)
- . A man purchased equal number of bananas at two different rates-one at the rate of 8 taka per dozen and the other at the rate of 10 taka per dozen. After that, he sold those bananas at an average rate of 11 taka per dozen and thus made a profit of 100 taka. How many dozens of banana did he purchase altogether?
- In a cricket match Tamim played 120 balls. His number of boundaries was twice the number of over boundaries. He took 12 single runs, no 2 or 3 runs, & could not score from 33 deliveries. How many runs did he score?
- A reservoir has two pipes, A and B. A can fill the reservoir 5 hours faster than B. If both together fill the reservoir in 6 hours, the reservoir will be filled by A alone in-
- On an average Dr. Maruf attends 12 patients per day and Dr. Mehdi attends 16 patients per day. If Dr. Maruf's charge is1 1/2 times of Dr. Mehdi who earns Tk. 72,000 per month, what is the monthly income of Dr. Maruf?
- A number is divided by 4. The result is divided by 3. The final result is 2. What was the original number?
- The cost of two litres of Oil and its container is Tk. 100. If the cost of the container is Tk. 23 less than the cost of one litre of Oil, what is the cost of one litre of Oil?
- ঢাকা থেকে চট্টগ্রাম এর দূরত্ব ১৮৫ মাইল। চট্টগ্রাম থেকে একটি বাস ২ ঘণ্টায় প্রথম ৮৫ মাইল যাওয়ার পর পরবর্তী ১০০ মাইল কত সময়ে গেলে গড় ঘন্টায় ৫০ মাইল যাওয়া হবে?
- Asif is now 14 years older than saif. If in 10 years Asif will be twice as old as Saif. How old will Asif be in 7 years?
- in an exam, 90% passed History and 85% passed English if none of the students failled in both subjects and 225 passed in both subjects, calculate the number of students who have attended the exam.
- কোনো বৃত্তের ব্যাসার্ধ যদি ২০% কমে, তবে উক্ত বৃত্তের ক্ষেত্রফল কত % কমবে ----
- একটি প্রতিষ্ঠানের ৪০% কর্মচারী আন্ডারগ্রাজুয়েট অবশিষ্ট কর্মচারীদের ৫০% গ্রাজুয়েট এবং অবশিষ্ট ১৮০ জন পোস্ট গ্রাজুয়েট। প্রতিষ্ঠানটির কত জন কর্মচারী গ্রাজুয়েট?
- A company has 3,600 employees of which 1/3 are clerks. If the clerical staff is reduced by 1/3, what percent of the total number of remaining employees would be clerical staff?
- টি টুয়েন্টি ক্রিকেটে ষোলটি দল নক আউট পদ্ধতিতে ফাইনাল পর্যন্ত খেললে মোট কয়টি ম্যাচ অনুষ্ঠিত হবে ?
- Lima is 6 years older than her sister Sharmin, and Jamal is 5 years older than Lima. If the total of their ages is 41, how old is Jamal?
- The population of City X is 40% percent of the population of City Y. The population of City X is what percent of the total population of city X and City y together?
- যদি 2 × 3 = 812, 4 × 5=1620 হয় তবে 6 × 7 = কত?
- The length of each side of square A is increased by 100 percent to make square B. Again the length of each side of square B is increased by 50 percent to make square C. By what percent is the area of square C greater than the sum of the areas of square A and B?
- Jasim went for shopping and spent 1/3 of his money for a bat and another Tk 5 for a ball. If Jasim still had 1/2 of his money left, how much money did Jasim have originally?
- Find the smallest number which when divided by 16 and 20 will have a remainder of 8 and 12 respectively.