The average marks obtained by Raghav in 12 tests is 24. Zubeida has maintained an average of 23 so far but has taken only 9 of the tests. If each test is out of 30, at least how much Zubeida score in any one of the remaining three tests to still have a chance to match Raghav's performance?
B is thrice as efficient as A and C is 0.75 times as efficient as A. What is the ratio of number of days taken by A, B and C when they work individually?
A monopoly is a market that has a single seller of a unique product in the market. He does not have any competition in the market as he has no substitute product for the product he is selling.