Answer:
1022 minutes
Step-by-step explanation:
Let x be the number of minutes the executive used the phone
There is a base charge of $35 and only minutes greater than 900 min are charged at the rate of $0.40 per minute
So total bill A = 35 + 0.4(x-900)
We know the bill was $83.80
So we can rewrite the equation as
35 + 0.4(x-900) = 83.30
and solve for x
To make it easier for computational purposes
1) Multiply both sides by 10
2) Perform individual multiplication
3) Subtract 350 from both sides
4) Simplify
5) Divide both sides by 4
6) Simplify
7) Add 900 to both sides to isolate x
8) Simplify to obtain x
Answer: The executive used the phone for 1022 minutes that month