Problem: how many 3 digit number formed by using 23 , 45 , 67 once such that number is divisible by 15 .
Rationale: 4 * 2 * 1 = 8 at one ' s place only 5 will come and at ten ' s place 4 and 7 can be placed , and at 100 th place rest of the 4 digits can come . . . so the answer is 8 answer : a
annotated_formula: add(divide(divide(45, 3), 3), const_3)