Answer:
-15/8 or -1 7/8, 1.875
Step-by-step explanation:
The number of permutations of the 25 letters taken 2 at a time (with repetitions) is:

The number of permutations of the 9 digits taken 4 at a time (with repetitions) is:

Each permutation of letters can be taken with each permutation of digits, therefore the total number of possible passwords is:
A Hope Fully Im Right / Im pretty sure thats the answer
So, she has 550 dollars saved. If the junior season pass costs 315, you subtract that from 550. You should then have 235 dollars. Next, you divide 235 by 45 dollars per lesson, and you should get 5.22. You can't buy half a lesson, so she only has enough for 5 lessons.
The discriminant is b²-4ac
when the discriminant is 0, there is only one solution.