Answer:
Hey what'sup?
You need to dig a little in, for what it's actually meaning
Here the total is 720 right?
Which came from the materials and the labors work in hourly basis
So it's like
Cost of the material + no of hours = bill
We don't know what the no of hours are, so let's assume it as 'x'
Hence the required equation is
375+35*x=720
35*x = 720-375
35*x = 345
Therefore x=345/35 =9.8
Therefore they worked for 9.8 hours or approximately 10 hours
Peace out
