If we call the number "x" then:
x*25%=21
x*25/100=21
x=21*4
x=84
Hope this helps. :)
C = 150000 + 17n
where,
C = Total Cost per year = Fixed Cost + Variable Cost
n = Number of Widgets produced each year
17n = Variable Cost
150000 = Fixed Cost
I'm not really good at math but I would like to help.
If each call is $.08, then the card can call last for 250 minutes.
The call lasted 202 minutes. Divide 16.16 by .08.