Mathematical operations
- If 2 * 3 = 13, 3 * 4 = 25 and 4 * 5 = 41, then 5 * 6 = ? Answer: A. 61 Answer: (A) 61 2² + 3² = 13 , 3² + 4² = 25 , 4² + 5² = 41 . So a * b = a² + b² . 5 * 6 = 25 + 36 = 61. 1
- If A means ‘+’, B means ‘−’, C means ‘×’ and D means ‘÷’, then what is the value of 18 D 3 C 4 A 6 B 5? Answer: C. 25 Answer: (C) 25 Replace the letters: 18 ÷ 3 × 4 + 6 - 5 . BODMAS: 18 ÷ 3 = 6 , 6 × 4 = 24 , 24 + 6 - 5 = 25 . 1
- If ‘+’ means ‘×’, ‘−’ means ‘+’, ‘×’ means ‘÷’ and ‘÷’ means ‘−’, what is the value of 8 + 3 − 12 × 4 ÷ 5? Answer: D. 22 Answer: (D) 22 After replacing the signs: 8 × 3 + 12 ÷ 4 - 5 = 24 + 3 - 5 = 22 . 1
- If '×' means '+', '+' means '÷', '−' means '×' and '÷' means '−', what is the value of24 + 6 × 5 − 3 ÷ 4 ? Answer: C. 15 Answer: (C) 15 Replace the signs: 24 ÷ 6 + 5 × 3 - 4 . = 4 + 15 - 4 = 15 . 1
- If '+' means '×', '×' means '−', '−' means '÷' and '÷' means '+', what is the value of16 − 4 + 3 × 5 ÷ 2 ? Answer: A. 9 Answer: (A) 9 Replace the signs: 16 ÷ 4 × 3 - 5 + 2 . 16 ÷ 4 = 4 , 4 × 3 = 12 , 12 - 5 + 2 = 9 . 1