KA-0154●●○4 points, difficulty 2 of 34 ptLevel 7–8not yet calibratedIn a class of 30 students, 18 play football and 15 play chess. Exactly 7 students do both. How many students play neither?CNT-10Inclusion–exclusion with two setsalso CNT-09, CFT-01
KA-0155●●○4 points, difficulty 2 of 34 ptLevel 7–8not yet calibratedA photograph measures 8 cm by 12 cm. It is enlarged so that the shorter side becomes 20 cm, and the shape is not distorted. How long is the longer side of the enlargement?GEO-16Scaling and similar figuresalso NUM-11, CFT-11
KA-0156●●○4 points, difficulty 2 of 34 ptLevel 7–8not yet calibratedA pattern is built in rows. The first figure has 1 row, the second has 2 rows, and so on. In every figure, the first row has 1 dot, the second has 3 dots, the third has 5 dots, and each row after has 2 more dots than the one above it. How many dots are in the eighth figure?PAT-04Growth patterns and figurate numbersalso CFT-03, PAT-02