Mean marks of 50 students were found to be 78.4. But later it was detected that 95 was misread as 59 and 25 was misread as 52. What is the difference between correct mean and incorréct mean ?

Four years ago, the average age of A and B was 20 years. If today average age of A, B and C is 25 years, what will be age of C after 7 years?

The combined age of a man and his wife is 6 times the combined age of their children. Two years ago their combined age was 10 times the combined age of their children; and six years later their combi…

The mean of p, q, r, s and t is 280. If the mean of p, r and t is 240, what is the mean of q and s?

Ramesh scores in five math tests are 89, 75, 78, 84 and 83. What does he need to score in the next test for his final average in all the tests to be at least 82?

The average marks of 13 papers are 40. Average of first 7 is 42 and last 7 is 35. Marks obtained in the 7th paper are