If × stands for -, ÷ stands for +, + stands for÷, - stands for ×, then what is the value of 15 - 5 ÷ 5 × 20 + 10 ?

Question

Accepted Answer

To solve the problem, we need to substitute the given symbols with their respective operations according to the instructions:

- × stands for -
- ÷ stands for +
- + stands for ÷
- - stands for ×

The original expression is: 15 - 5 ÷ 5 × 20 + 10

Substituting the symbols with the correct operations, we get:

15 × 5 + 5 - 20 ÷ 10

Now, let's solve the expression step by step, following the order of operations (BODMAS/BIDMAS - Brackets, Orders (i.e., powers and roots, etc.), Division and Multiplication (from left to right), Addition and Subtraction (from left to right)):

1. Perform the multiplication: 
   15 × 5 = 75

2. Perform the division:
   20 ÷ 10 = 2

3. Substitute these values back into the expression:
   75 + 5 - 2

4. Perform the addition:
   75 + 5 = 80

5. Perform the subtraction:
   80 - 2 = 78

Thus, the value of the expression is 78, which corresponds to Option 2.

Explanation for why other options are incorrect:

- Option 1 (70): This result could arise from incorrect substitution or miscalculation in the order of operations.
- Option 3 (75): This result might occur if the division and subtraction were not performed correctly.
- Option 4 (73): This result could be due to an error in either the substitution of operations or the sequence of calculations.

Therefore, based on the correct substitution and calculation, Option 2 (78) is indeed the correct answer.