To find the basic charge for telephone usage, we need to subtract the taxes from the total bill.
Let's denote:
x as the basic charge for telephone usage.
Given:
- 5% sales tax
- 15% excise tax
The total bill is $120.
We know that:
- Sales tax = 5% of x
- Excise tax = 15% of x
So, the total bill can be expressed as:
Total bill = x + Sales tax + Excise tax
Given that the total bill is $120:
120 = x + 0.05x + 0.15x
First, let's find the total tax:
Total tax = Sales tax + Excise tax
Total tax = 0.05x + 0.15x = 0.20x
So, we have:
120 = x + 0.20x
120 = 1.20x
Now, divide both sides by 1.20 to solve for x:
x = 120 / 1.20
x = 100
Therefore, the basic charge for telephone usage is $100.