Achess team has 26 members. however, only 16 members attended the last meeting: half of the girls attended but all of the boys attended. how many boys are on the chess team?

6 boys

Explaination: because if only 16 members (out of total of 26) attended that means that there were 10 who didnt. It also says that all of the boys went, so that remaining 10 can't be any boys. (so they are girls) And finally it says half of the girls went so if there are 10 girls who didn't and only half went that must mean that there are 20 girls. So with 20 girls and 26 total members on the chess team, then there must be 6 boys.