If 7#5 means 7² + √5 and 6+4 means 6 - 4², then what is the value of 30+5#9?
2016
If 7#5 means 7² + √5 and 6+4 means 6 - 4², then what is the value of 30+5#9?
- A.
14
- B.
28
- C.
8
- D.
34
Attempted by 24 students.
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Correct answer: B
1. Identify the decoding rules: a # b = a² + √b and a + b = a - b². 2. Evaluate the expression 30 + 5 # 9 sequentially from left to right, starting with 30 + 5. 3. 30 + 5 becomes 30 - 5² = 30 - 25 = 5. 4. Substitute this result into the remaining expression: 5 # 9 becomes 5² + √9 = 25 + 3 = 28. Final Answer: Option B