Step-by-step explanation:
The monthly fixed charges by mobile company = $40
The cost of sending each text message = 0.05 cents
Now, 100 cents = 1 dollar
⇒ 1 cent =$ [tex](\frac{1}{100} )[/tex]
⇒ 0.05 cent s =$ [tex](\frac{1}{100} \times 0.05) =0.0005[/tex]
Also, the number of text messages send = m
So, the cost of sending m text message = m x ( cost of 1 text )
= m x ( $ 0.0005) = 0.0005 m
Now, Total bill = Fixed rate + cost of m texts
⇒ A =$40 + $ 0.0005 m
Hence, the monthly cost of cell phone is A = 40 + 0.005 m