# Q. If a+b means a-b; a-b means axb; axb means a÷b; a÷b means a+b, then what is the value of 10+30-100 x 50÷25? (Operations are to be replaced simultaneously)

a) 15

b) 0

c) -15

d) -25

Correct answer: d) -25

##### Question from UPSC Prelims 2024 CSAT Paper

**Explanation:**

Let’s approach this step-by-step, replacing the operations as given in the question:

1) First, let’s replace the operations simultaneously:

10+30-100×50÷25 becomes 10-30×100÷50+25

2) Now, let’s solve this using the standard order of operations (PEMDAS):

a) First, division: 100÷50 = 2

10-30×2+25

b) Next, multiplication: 30×2 = 60

10-60+25

c) Now we can perform the operations from left to right:

10-60 = -50

-50+25 = -25

3) Therefore, the final answer is -25.