Using the fundamental counting theorem, we have that:
- 648 different area codes are possible with this rule.
- There are 6,480,000,000 possible 10-digit phone numbers.
- The amount of possible phone numbers is greater than 400,000,000, thus, there are enough possible phone numbers.
The fundamental counting principle states that if there are p ways to do a thing, and q ways to do another thing, and these two things are independent, there are ways to do both things.
For the area code:
- 8 options for the first digit.
- 9 options for the second and third.
Thus:

648 different area codes are possible with this rule.
For the number of 10-digit phone numbers:
- 7 digits, each with 10 options.
- 648 different area codes.
Then

There are 6,480,000,000 possible 10-digit phone numbers.
The amount of possible phone numbers is greater than 400,000,000, thus, there are enough possible phone numbers.
A similar problem is given at brainly.com/question/24067651
Answer:
Step-by-step explanation:
we can use the trigonometric function in a right triangle
cos x = adjacent side to the angle /hypothenuse
cos 36°= x/10 ; multiply both sides by 10
10 * cos 36° = x ; make sure your calculator mode is in degrees
8.1 = x
Answer:
Side length of square (inches): 1 ,2, 4, 7
Perimeter of square (inches). : 4, 8, 16, 28
Step-by-step explanation:
Ratio is 1:4 (S:P).
So:
#:8, #=2. This is because 2/8 and 1/4 both = 0.25.
#:16, #=4. 4/16=0.25
7:#, #=28. 4x7=28, 7/28=0.25
Hope that helps
Answer:Albert spent more on video games and 1/2>0.4
But Rosa spent more on pizza 2/5>.25
Step-by-step explanation: Rosa spent most of her allowance while Albert spent the least amount so Rosa spent more
Answer:
A
Step-by-step explanation:
Hopefully this helps