## Algebra 1

A Venn diagram can help solve the problem by determining how many patients have A antigens as well as B antigens. The main strategy in completing the Venn diagram is to work backwards. We know 10 patients have both the A and B antigens, and we also know 25 patients have the A antigens. $25 - 10 = 15$ 15 patients have only A antigens (and no B antigens). We know 10 patients have both the A and B antigens, and we also know 17 patients have the B antigens. $17- 10 = 7$ 7 patients have only B antigens (and no A antigens). $15 + 10 + 7 + 30 = 62$