Answer:
4
Step-by-step explanation:
20 x 4 = 80
so 1 per 20 minuets,and 4, 20 min. magazines would mean he needs 4 to make it to 80
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:
8
5
-1
-4
Step-by-step explanation:
Answer:
The given fraction
reduces to 
Step-by-step explanation:
Consider the given fraction 
We have to reduce the fraction to the lowest terms.
Consider numerator 
We can take x² common from both the term,
Thus, numerator can be written as
Given expression can be rewritten as ,

We can now cancel
from both numerator and denominator,


Thus, the given fraction
reduces to 