Two trains are running in opposite directions at the same speed. If the length of each train is 150 m and they cross each other in 15 sec, find the speed of each train (in km/hr).
In an examination, the average score of a student was 71.9. If the student would have got 28 more marks in English, 22 more marks in Mathematics, 16 more marks in Computer Science, 14 more marks in History, 10 less marks in Hindi, and retained the same marks in other subjects, then the average score would have been 80.65. How many subjects were there in the examination?
What is the ratio in which product A, costing ₹70 per 100 grams, should be mixed with product B, costing ₹100 per 100 grams, so that on selling the mixture at ₹1.20 per gram, a profit of 25% is achieved?
Mr Rao purchased a laptop for ₹45,000. After a few months, as his office provided another laptop, he sold it at a loss of 12% to Mrs Sharma. After one year, she sold it to an engineering student for a profit of 12%. What is the amount the student had to pay?