A father said to his son, "n years back I was as old as you are now. My present age is four times your age n years back". If the sum of the present ages of the father and the son is 130 years, what is the difference of their ages?

Let $p, q, r$ and $s$ be distinct positive integers. Let $p, q$ be odd and $r, s$ be even. Consider the following statements :

1. $(p - r) (qs)$ is even.

2. $(q - s) q^2 s$ is even.

3. $(q + r)^2 (p + s)$ is odd.

Which of the statements given above are correct?

If the sum of the two-digit numbers AB and CD is the three-digit number 1CE, where the letters A, B, C, D, E denote distinct digits, then what is the value of A?

The total cost of 4 oranges, 6 mangoes and 8 apples is equal to twice the total cost of 1 orange, 2 mangoes and 5 apples.

Consider the following statements:

1. The total cost of 3 oranges, 5 mangoes and 9 apples is equal to the total cost of 4 oranges, 6 mangoes and 8 apples.

2. The total cost of one orange and one mango is equal to the cost of one apple.

Which of the statements given above is/are correct?