Of the 30 students in my class, 11 practice taekwondo, 11 play piano, and 20 take lessons at MS. 4 students play piano and go to MS, 3 students do taekwondo and play piano, 5 students go to MS and practice taekwondo, and 3 students do none of these. How many students do all 3?
Are you sure you posted the numbers correctly? In particular the 20 number.....but it could be oneof the others....is there only 30 students?
The numbers don't add up....here is a Venn Diagram (bottom nember is 13)