The number n is a 2-digit number. when n i divided by 10, the remainder is 9, and when n is divided by 9, the remainder is 8. what is the value of n?

Think of numbers that when they are divided by 10, the remainder is 9.
So numbers like: 19, 29, 39, 49, 59, 69, 79, 89, and 99.

Now numbers that when they are divided by 9, the remainder is 8.
So numbers like: 17, 26, 35, 44, 53, 62, 71, 80, 89, and 98.

Now the number that is alike from the two sets of numbers is n.
n=89

Double check your work.
Divide 89 by 10. Remainder of 9
Divide 89 by 9. Remainder of 8.

Hope this helps :)