Final answer:
The markup rate when the water consumption price per cubic meter raises from php 22.50 to php 23.15 is calculated using the percentage increase formula. This equates to 2.89%, which corresponds to option B.
Step-by-step explanation:
The subject of the question is determining the markup rate when the water consumption price per cubic meter raises from php 22.50 to php 23.15. This is a mathematics problem specifically related to percentage increase calculation. The percentage increase can be calculated using the formula: (New Price - Old Price)/Old Price x 100%. Substituting the given values, this equates to: (23.15 - 22.50)/22.50 x 100% = 2.89%. So, the markup rate is 2.89%, option B.
Learn more about Markup Rate