bbyggigi6634 bbyggigi6634
  • 04-09-2017
  • Mathematics
contestada

How many 7 digit phone numbers are there assuming the first digit can't be a 0 or a 1?

Respuesta :

Аноним Аноним
  • 04-09-2017
The first digit can be any one of the numbers 2-9 That a total of 8 numbers.

The next 6 digits can be any permutation of 6  from the numbers  0 to 9.
(10 numbers)

nPr  =  n! / r!

so here we have  10P6  = 10! / 6!  =  10*9*8*7  =  5040

So final answer  is 8 * 5040 = 40,320
Answer Link

Otras preguntas

which of the following refers to the anxiety or discomfort we experience when we deviate from our own internal standards of right and wrong? a. moral inferiorit
1. When inspecting a heating system, you should always A. try to operate the system regardless of the conditions. B. open readily accessible acces
There are five cars in line at a stoplight. Each of these cars is a different color and different type of car. Diego is driving the red car. Ingrid is driving t
references are typically included on a résumé. true or false.
I need help on number 3
What is the definition of an equation?
The author of my brothers keeper emphasizes Jamie's conflict by?
What different from 58.7F to 92.6F
2 more than 3 times a number is 17 as an equation
if an organization’s competitive strategy relies on long-term relationships with the clients who purchase the organization’s goods and services, the organizatio