SOLUTION: Julia is starting her own on-line business selling jewellery that she makes. It cost her $3000 to buy a new computer, and her monthly expenses for Internet service and materials av

Algebra ->  Coordinate Systems and Linear Equations  -> Linear Equations and Systems Word Problems -> SOLUTION: Julia is starting her own on-line business selling jewellery that she makes. It cost her $3000 to buy a new computer, and her monthly expenses for Internet service and materials av      Log On


   

Question 975639: Julia is starting her own on-line business selling jewellery that she makes. It cost her $3000 to buy a new computer, and her monthly expenses for Internet service and materials average about $170 per month. If her revenue for each month averages about $420, how long will it be before she starts to earn a profit?
Answer by Fombitz(32388) About Me  (Show Source):
You can put this solution on YOUR website!
The equation for costs is
C%28t%29=3000%2B170t
where t is measured in months.
The equation for revenues is,
R%28t%29=420t
Profit equals revenue minus costs,
Find when P reaches zero.
P=R-C
P=420t-3000-170t
P=250t-3000
250t=3000
t=3000%2F250
t=12months
So in the 13th month from starting she'll have a profit.