Answer:
 Php 770.00
Explanation:
The cost of labor is ...
 (hours) × (hourly rate)
 = (3 h) × (Php 150.00/h) = Php 450.00
The total cost is ...
 total cost = cost of labor + cost of parts
 = (Php 450.00) + (Php 320.00) = Php 770.00
Randolf owes Mr. Solidarios Php 770.00 for the repair.