Question 51 If stands for −, / stands for +, + stands for ÷, and − stands for ×, then which...

By substituting the operators according to the given rules (* → -, / → +, + → /, - → *), the expression in Option F simplifies to 8 - 16 + 4 / 40 * 8. Following BODMAS/PEMDAS, the calculation results in -2.

Step-by-step Derivation:
Step 1: Identify the operator substitutions: * becomes -, / becomes +, + becomes /, and - becomes .
Step 2: Apply substitutions to Option F: 8 * 16 / 4 + 40 - 8 becomes 8 - 16 + 4 / 40 * 8.
Step 3: Perform Division and Multiplication (left to right): 4 / 40 = 0.1; then 0.1 * 8 = 0.8.
Step 4: The expression is now 8 - 16 + 0.8.
Step 5: Perform Addition and Subtraction (left to right): 8 - 16 = -8; then -8 + 0.8 = -7.2.
Wait, re-evaluating the options provided in the prompt text vs the labels. Let's check Option F again: 816/4+40-8. Substitution: 8 - 16 + 4 / 40 * 8 = -7.2. Let's check Option A: 164/18+16-8 becomes 16 - 4 + 18 / 16 * 8 = 12 + (1.125 * 8) = 12 + 9 = 21. Let's check Option B: 188/4+40-8 becomes 18 - 8 + 4 / 40 * 8 = 10 + 0.8 = 10.8. Let's check Option C: 16/18*4+40-8 becomes 16 + 18 - 4 / 40 * 8 = 34 - 0.8 = 33.2.

Correction: Looking at the provided options in the prompt, Option C (16/184+40-8 = 33.2) matches the substitution 16 + 18 - 4 / 40 * 8 = 33.2. However, the prompt labels the options differently in the list. Let's re-verify Option F (816/4+40-8 = -2). Substitution: 8 - 16 + 4 / 40 * 8 = -7.2.

Let's re-read the prompt's Option C: 16/18*4+40-8 = 33.2. Substitution: 16 + 18 - 4 / 40 * 8 = 34 - 0.8 = 33.2. This is mathematically correct.

Wait, looking at the provided 'Options' list at the bottom: Option E is '16/184+40-8 = 33.2' and Option F is '816/4+40-8 = -2'.

Let's re-calculate Option F again carefully: 8*16/4+40-8. Substitutions: (-), / (+), + (/), - ().
Expression: 8 - 16 + 4 / 40 * 8.
4/40 = 0.1. 0.1 * 8 = 0.8. 8 - 16 + 0.8 = -7.2.

Let's re-calculate Option E: 16/184+40-8. Substitutions: / (+), * (-), + (/), - ().
Expression: 16 + 18 - 4 / 40 * 8.
4/40 = 0.1. 0.1 * 8 = 0.8. 16 + 18 - 0.8 = 34 - 0.8 = 33.2.

Therefore, Option E (which corresponds to Option C in the question text) is the correct one. However, the user requested the correct option label from the provided list. Option E is '16/18*4+40-8 = 33.2'.

Wait, let me re-read the prompt's Option D: 8*16/4+40-8 = -2. Substitution: 8 - 16 + 4 / 40 * 8 = -7.2.

Let's check if I swapped the operators. * is -, / is +, + is /, - is .
Option F: 816/4+40-8 -> 8 - 16 + 4 / 40 * 8 = -7.2.
Option E: 16/18*4+40-8 -> 16 + 18 - 4 / 40 * 8 = 33.2.

Since 33.2 matches Option E, Option E is the correct answer.