What is the rightmost digit preceding the zeros in the value of $30^{30}$?

421 and 427, when divided by the same number, leave the same remainder 1. How many numbers can be used as the divisor in order to get the same remainder 1?

A can X contains 399 litres of petrol and a can Y contains 532 litres of diesel. They are to be bottled in bottles of equal size so that whole of petrol and diesel would be separately bottled. The bottle capacity in terms of litres is an integer. How many different bottle sizes are possible?

Consider the following statements in respect of the sum $S = x + y + z$, where $x, y$ and $z$ are distinct prime numbers each less than 10:

1. The unit digit of $S$ can be 0.

2. The unit digit of $S$ can be 9.

3. The unit digit of $S$ can be 5.

Which of the statements given above are correct?