1 लेंस सूत्र 2 संयुक्त लेंस की फोकस दूरी | किरण प्रकाशिकी | 12th Physics |Chap 9 |Lec 5 |Gopal Sir

A man travels a certain distance at 12km/h and returns to the starting point at 9km/h. The total time taken by him for the entire journey is 2 1/3 hours. The total distance (In km) covered by him is: / एक व्यक्ति कोई निश्चित दूरी 12 किमी/घंटा की चाल से तय करता है और आरंभिक बिंदु पर 9 किमी/घंटा की चाल से लौटता है | पूरी यात्रा में उसे कुल 2 1/3 घंटे का समय लगता है | उसके द्वारा तय की गयी कुल दूरी ज्ञात करें |

An examination was held during the 2 weeks of April 3rd-Sunday to 16th Saturday. There was 1 paper for the six subjects - Physics, Chemistry, Biology, Maths, English and Hindi. Only 1 paper per day No exam on Saturdays and Sundays and Holiday on April 5th. Only 3 exams were there in a week. Chemistry was before Biology and Maths was on the next day of Hindi. The day on which the paper of biology and maths were held was the same, while that for chemistry and physics was also the same. There was no exam for 3 days between Physics and the exam prior to it. Hindi exam on Tuesday and one exam between Hindi and English exam. There was at least a gap of one day between any 2 science paper. Which of the following exam was held on April 12th ?

There are ten exams to be conducted from 9 to 13 of a month. There are two time slots for every day, morning slot and evening slot. The maximum marks of these exams are from 70 to 160. The maximum marks of every subject are unique. The time durations of the exams is from the range of 1hr to 5hr. The time duration is also unique for each subject. The subjects are Math, English, Physics, Bio, Chemistry, Economices, History, Home Science, Geography and Accounts. The first exam is of math and of 2hrs. The time duration of last exam is 15 minutes more than first exam. The exam of English is of 80 marks and on the same day of the exam of math. Total marks of the exams of first day are 180 marks. There are two exams between history and accounts. The last exam is of accounts and of 110 marks. There are three exams between English and the exam which is of 90 marks. The exam of physics is in morning and it is on an even date. The exam of 3hr and 5hr are on the same day. The sum of timings of math and physics is 5hr. The exam of 130 marks and 90 marks are on the same day. The exam of chemistry is not of 90 marks. The exam of geography is of 4^(1//2) hrs. and on the last day. The exam of home science is on an even date and of least marks. The exam of chemistry is before exam of economics. The exam of 150 marks is of maximum time duration. The exam of economics is of economics is of least time duration. The sum of time duration of economics and history is of 5hrs. The exam of Chemistry is of 3^(1//2) hrs. duration. The maximum marks of physics is 30 marks less than that of biology. The maximum marks of 4^(1//2) hrs. exam is 30 marks more than marks of accounts. History is of maximum marks. The maximum marks of home-science are least of all. Which two exams are scheduled for 10^(th) of the month?

In a survey of 25 students, it was found that 15 had taken Mathematics, 12 had taken Physics and 11 had taken Chemistry, 5 had taken Mathematics and Chemistry, 9 had taken Mathematics and Physics, 4 had taken Physics and Chemistry and 3 had taken all the three subjects. Consider the following statements : 1. The number of students who had taken only one subject is equal to the number of students who had taken only two subjects. 2. The number of students who had taken at least two subjects is four times the number of students who had taken all the three subjects. Which of the above statements is/are correct ?