If x - y = 6 and xy = 40, then  find $$ {x^2+y^2}$$

(x+2y) (x² + 4y² – 2xy) equal to- 

The total number of students in sections A and B of a class is 72. The ratio of the number of students in A and B is 7 :5 . The average weight (in kg) of the students in section B is 20% more than that of the students in section A. If the average weight of all the students in the class is 52 kg, then what is the average weight (in kg) of the students in section B?

A's 2 days work is equal to B's 3  days work. If A can complete the work in 8 days, then to complete the work B will take: 

1, 3, 5, 7, ………total average of 25^th number  is:

A person borrows 5,000 for 2 years at 4 % per annum simple interest. He immediately lends it to another person at $$6{1\over 4}\%  $$ per annum simple interest for 2 years. His gain in this transaction is 

The ratio between the length and breadth of a rectangular park is 3: 2. If a man cycling along the boundary of the park at the speed of 12 Km./hr. completes one round in 8 min, then the area of the park in sq.m is – 

In an examination in which full marks were 500. A got 25% more than C, C got 20% less than D. If A got 360 marks. What percentage of full marks was obtained by D ?