Answer:
32 hours
Step-by-step explanation:
Let after x hours the charges of A and B are same,
Given,
For painter A,
Fixed charges = $ 376,
Additional charges per hour = $ 12,
So, the total charges for x hours = ( 376 + 12x ) dollars
For painter B,
Fixed charges = $ 280,
Additional charges pet hour = $ 15,
So, the total charges for x hours = ( 280 + 15x ) dollars
Thus,
376 + 12x = 280 + 15x
12x - 15x = 280 - 376
-3x = -96
x = 32
Hence, for 32 hours their cost will be same.