SASMO 2027 · Grades 4-5 · SET 004 · Self-study Question 23

Define a ○ b = (a + 1) × b.
(a) Calculate 4 ○ 7.
(b) Calculate (7 ○ 2) ○ 9.
(c) Find x if (x ○ 3) ○ 1 = 13.
Enter answers (a),(b),(c) in order, separated by commas.