C

9000089003

Level: 
C
Students from a class bought a snack in the school lunch-room. There were 31 students in the class in total. Altogether 8 students had snack from their home and they did not buy anything. Altogether 12 students bought hamburger and 15 students bought hot-dog. How many students bought both hamburger and hot-dog?
4
19
8

9000089001

Level: 
C
Students from a class have a possibility to work in mathematical and physical hobby groups. There are 31 students in the class. From the total, 21 students are members of mathematical group. Some of the students are members of both groups, but there are 10 which are members of just one group. There are 3 students which are not members of any of those groups. How many students are members of both mathematical and physical groups?
18
16
19