Bus tickets in a certain city contain four numbers, U,
V , W, and X. Each of these numbers is equally likely to
be any of the 10 digits 0, 1, 9, and the four numbers
are chosen independently.A bus rider is said to be lucky if
U + V =W + X.What proportion of the riders are lucky?

Do you have a question about the problem?

We will be happy to help you, but first we need to know what the issue is.

Hello kuldeep. We're happy to help, but first please show us your attempt at this. One suggestion I would make is try this same problem with the four digits being limited to just three choices - 0, 1, and 2 - so there are only 9 possible combinations of U and V to think about. Then extend it to ten possible digits. Post back with your attempt and we'll help if you get stuck.