If 5 notebooks cost Rs. 125, how much will 8 notebooks cost?

The correct answer is Rs. 200. This is a direct proportion problem solved using the unitary method.

Step-by-Step Solution

• Step 1 – Find the cost of one notebook:
  
  Cost of 5 notebooks = Rs. 125
  
  Cost of 1 notebook = 125 ÷ 5 = Rs. 25
• Step 2 – Calculate the cost of 8 notebooks:
  
  Cost of 8 notebooks = 8 × 25 = Rs. 200
• Verification Using Proportion:
  
  5 : 125 :: 8 : x
  
  x = (125 × 8) ÷ 5 = 1000 ÷ 5 = 200. Confirmed.
• Why Other Answers Are Wrong:
  
  Rs. 150 would mean cost per notebook is 18.75, not 25.
  
  Rs. 175 and Rs. 250 are also incorrect results of miscalculations.

Hence, 8 notebooks will cost Rs. 200.