Answer:Joe plumbing is cheaper option
J(t)=45t
For Joe 's billing rate .
For Leyla needs 3 hours of work.
t =3hours.
Joe will charge 45×3=€135
Mark charges $4O per hour and $25 trip charge to do Layla 3 hour job mark will charge :
(40×3 )+25 =$145
Joe is cheaper by $10
For Leyla Joe is cheaper and she will save $10
Explanation: