m ≥ 1395 minutes
Step-by-step explanation:
Monthly fee = $15
fee paid per minute of use = $0.05
let the number of minutes she used = m
The least amount she has been charged = $84.75
least is written as ≥ $84.75
The equation:
Monthly fee + fee per minute(number of minutes) = The total charge
The equal sign changed below since the question mentioned the least amount
$15 + 0.05(m) ≥ $84.75
15 + 0.05m ≥ 84.75
To get the possible number of minutes, we will solve for m:
15 + 0.05m ≥ 84.75
subtract 15 from both sides:
0.05m ≥ 84.75 - 15
0.05m ≥ 69.75
divide both sides by 0.05:
m ≥ 69.75/0.05
m ≥ 1395 minutes
The possible number of minutes she has used her phone in a month is at least 1395 minutes