Question 1027938
Hi there,
the cost of a plumbers services 
is given by the formula: c =50+40t.
c is the cost in dollars and t is 
the time worked in hours. 
Cost = 50 + 40t
$330 = 50 + 40t
330 - 50 = 40t
t = (330 - 50)/40
t = 7 hours
Hope this helps :-)