If the pair of linear equations ax + 3y + (3 - a) = 0 and 12x + ay - a = 0 has infinitely many solutions, then the value of a is:

Find the number of solutions for the pair of linear equations: 5x − 7y + 28 = 0 and 10x + 14y − 28 = 0.

If 2p3 - 57 = 3, then the value of p is:

The cost of 2 sarees and 4 shirts is Rs. 1600. With the same amount of money, one can buy 1 saree and 6 shirts. If someone wants to buy 12 shirts, how much amount does he/she have to pay?