Respuesta :

TheBreeze

a) C = 40 + 30t

b) 280 = 40 + 30t

30t = 240

t = 8

The plumber worked 8 hours
C is equal to (30 x t) + 40
C = 30t + 40
we are given that C = 240
280=30t + 40
solve for t
t = 8 hrs