Explanation:

Let’s break it down:

- Let the cost price = Rs C.

- Selling at Rs 1,188 gives profit percent = x.

So, 1,188 = C + x% of C = C(1 + x/100).

- Selling at Rs 1,435.50 gives profit percent = x + 25.

So, 1,435.50 = C(1 + (x + 25)/100).

Now let’s set it up:

1,188 / C = 1 + x/100

1,435.50 / C = 1 + (x + 25)/100

Subtract the first from the second:

(1,435.50 - 1,188) / C = [(x + 25) - x]/100

247.5 / C = 25/100

247.5 / C = 0.25

C = 990

Now plug back in:

1,188 = 990(1 + x/100)

1 + x/100 = 1,188/990 = 1.2

x/100 = 0.2

x = 20

Here’s what that means for the options:

Option 1: 18 (No — doesn’t work)

Option 2: 15 (No — too low)

Option 3: 20 ( This checks out; math matches)

Option 4: 10 (No — too low)

So, option 3 is correct. x = 20.