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
There was a 200% increase
Answer:
4w+120.
Step-by-step explanation:
She downloads 4 songs for every week which is represented as 4w, and she started with 120 songs which is represented as +120.
Answer:

Step-by-step explanation:
The 3 roots are given out of which 2 are real and 1 is imaginary. For a polynomial of least degree having real coefficients, it must have a complex conjugate root as the 4th root. Therefore, based on 4 roots, the least degree of polynomial will be 4. Finding the polynomial having leading coefficient=1 and solving it based on multiplication of 2 quadratic polynomials, we get:

Answer:
option 3, 45
Step-by-step explanation:
3x - 9° + 30° + 24° = 180° (angle sum property of a triangle)
3x - 9° + 54° = 180°
3x + 45° = 180°
3x = 180° - 45°
3x = 135°
x = 135/3
x = 45°
therefore, option 3 is the correct option