Question

Could someone help please
a cellular company offers a contract for which the cost C, in dollars of t minutes of telephoning is given by C=0.25(t - 300) + 80.95, where it is assumed that t > or = to 300 minutes.
what times will keep costs between $125.45 and $151.70?
For the cost to be between $125.45 and $151.70, the telephoning time must be between ----minutes and ----minutes

Answer 1

c=0.25(t-300)+ 80.95
when c= 125.45,
125.45=0.25(t-300)+80.95
44.5=0.25(t-300)
0.25t=44.5+75
t=478 min

151.70=0.25(t-300)+80.95
70.75+75= 0.25t
t=583

Answer 2

thanks c0c0ple
the final answer is 478 minutes and 583 minutes correct

Answer 3

ur welcome ^^