Answer:
- There are 20,000 number available.
Step-by-step explanation:
To determine how many phone numbers are available you need to know how many digits the number contains.
I will assume the same number of digits for other similar questions, i.e. 7.
With 7 digits, the numbers that begin with 373 or 377 can be of the form 373XXXX or 377XXXX.
Where each X can be any digit 0 - 9. Then, there are 10 different options for each X.
Thus, there are 10×10×10×10 = 10,000 different numbers starting with 373 and other 10,000 different numbers starting with 377.
In total, there are 20,000 numbers available.