The average of eleven numbers is 68. The average of the first numbers is 78 and that of the next four number is 63. The 9^th number is two time the 11^th number and the 10^th number is 4 less than the 11^th number. What is the average of the 9^th and 11^th numbers?

529 mangoes are distributed to Vivek Amit and Ajay in the ratio of $$ {1\over 2},{2\over 3} ,{3\over4}$$ respectively. So tell me how many mangoes Ajay will get?

α and β  is two root of a equations $$2x^2-7x+ 12=0 $$ then the value of $$ {α \over β }  + {β \over α }=? $$

The average age of students in a class is 15.8 years. The average age of boys in the class is 16.4 years and that of the girls is 15.4 years. The ratio of the number of boys to the number of girls in the class is:

Nathu and Buchku each have certain number of oranges. Nathu says to Buckhu, " If you give me 10 of your oranges, I will have twice the number of oranges left with you “. Buckhu replies, " If you give me 10 of your oranges, I will have the same number of oranges as left with you." What is the number of oranges with Nathu and Buckhu , respectively ?

The value of $$ cot\ {π\over 20}\ cot{3π\over 20} \cot{5π\over20}\ cot{7π\over 20}\ cot {9π\over20}$$ is:

If the selling price of a product is multiplied by 2, the resulting profit is 6 times the original profit. What is the original profit percentage?