Answer:
The chances given on the page for winning the jackpot ("1 in 302,575,350") is correct.
Explanation:
We just have to verify that the number of possible lottery tickets is 302, 575, 350.
We have six numbers
N1 - N2 - N3 - N4 - N5 - N6
The first five numbers are a combination of 5 from 70. This is a combination because for example, 1,2,3,4,5 is the same as 5,4,3,2,1.
The total number of combination of x from n is given by the following formula:

The sixth number can be any of the 25 values.
The total number of combinations is:

This means that the chances given on the page for winning the jackpot ("1 in 302,575,350") is correct.