2.03 In a contest, three problems, A, B, and C are posed. 25 of the participants solve at least one problem each. Of all those who don’t solve problem A, the number of those who solve B is twice the number of those who solve C. The number of participants who only solve problem A is one more than the number of those who solve A and at least one other problem. Of all participants who solve just one problem, half do not solve problem A. How many participants solve only problem B?
2.04 How many four-digit integers (i.e., between 1000 and 9999) cannot be changed to multiples of 1892 by replacing up to three of their digits?
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