For what value of k, 2x + ky = 6 has equal values of x and y for its solution?

Sudesh is twice as old as Seema. If six years are subtracted from Seema's age and 4 years are added to Sudesh's age, Sudesh will be four times Seema's age. How old were they 3 years ago?

A part of monthly expenses of a family on milk is fixed which is Rs.700 and remaining vary with the quantity of milk taken extra at the rate of Rs. 25 per litre. Taking quantity of milk required extra as x litre and total expenditure on milk Rs. Y. Write a linear equation representing the above information.

Solve the linear equations x – 2y = 8 and 5x + 3y = 1 by algebraic method.

The angles of a triangle are x, y and 40. The difference between the two angles x and y is 30. Find x and y.